Date and Time Tools: Calendars, Clocks and Time Zones

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Date and time tools handle a kind of arithmetic that looks simple and is quietly full of traps. Months have different lengths, some years carry an extra day, clocks run on two competing formats, and the world is divided into time zones that do not line up neatly. A single overlooked rule can throw a result off by a day, an hour, or a whole year. This guide is a map of the date and time tools on this site, grouped by the job each one does.

In this guide

Why date and time maths goes wrong

The calendar is not a regular system. Months range from 28 to 31 days. Most years have 365 days, but some have 366. The leap year rule even has an exception inside its exception: a year divisible by 4 is a leap year, except a century year, which counts only if it is also divisible by 400. The year 2000 was a leap year, but 1900 was not.

Clocks add their own confusion with two formats in daily use, and time zones add another layer on top. Any calculation that crosses these boundaries can drift if one rule is missed. A tool applies the rules the same way every time, which is the point of using one.

Calendar tools: dates, years and ages

The calendar tools work on dates and the years that hold them. The leap year checker tells you whether a given year has 366 days, and the common year checker confirms the reverse, both applying the divisible-by-400 rule so you do not have to.

The calendar date analyzer breaks a single date down into its details, such as the day of the week it falls on. The age calculator works out an exact age in years, months, and days from a birth date, handling the uneven month lengths automatically, and the date at percent of year tool finds the calendar date that sits a given percentage of the way through a year.

Clock tools: time of day

The clock tools work on times of day rather than dates. The clock time analyzer breaks a time down into its parts. The seconds since midnight and seconds till midnight tools convert a time of day into a plain count of seconds, which is how many systems store time internally.

For something more specific, the clock hand angle calculator works out the angle between the hour and minute hands at a given time. At three o’clock, for instance, the hands sit exactly 90 degrees apart.

Time format conversion

The 12-hour and 24-hour formats cause real, everyday confusion. The 12-hour format runs 1 to 12 twice a day with AM and PM to mark which half. The 24-hour format runs 00 to 23 once, with no AM or PM. The 24-hour time 15:00 is 3:00 PM, midnight is 00:00, and noon is 12:00.

The point where people slip is the boundary around midnight and noon, where the two systems do not map in an obvious way. The 12-hour to 24-hour converter and the 24-hour to 12-hour converter handle both directions without the guesswork.

Time zones

Time zones are the hardest part of date and time work. Zones differ from each other by whole hours, and in some places by half hours, and many regions shift their clocks seasonally for daylight saving. Working out what time a meeting falls in another country is a calculation people get wrong constantly.

The time zone difference calculator works out the gap between two zones, which is the figure you need to schedule a call across regions without waking someone at three in the morning. The full set of these tools lives in the time tools category, and each one runs in your browser with no signup.

Free date and time tools used in this guide

Frequently asked questions

How do I know if a year is a leap year?

A year is a leap year if it is divisible by 4, except for century years, which count only if they are also divisible by 400. 2024 is a leap year, and 2100 will not be.

What is the difference between 12-hour and 24-hour time?

The 12-hour format runs 1 to 12 twice a day with AM and PM. The 24-hour format runs 00 to 23 once. The 24-hour time 15:00 is the same as 3:00 PM.

How do I calculate someone’s exact age?

The age calculator works out years, months, and days from a birth date, handling the uneven lengths of the months for you.

Why is calculating across time zones difficult?

Zones differ by whole and sometimes half hours, and daylight saving shifts many of them seasonally, so the gap between two places is not always a fixed number.

Are these tools free?

Yes. Every date and time tool on the site is free, runs in your browser, and needs no account.

BMI Explained: What the Number Means and What It Misses

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BMI, short for body mass index, is a single number worked out from a person’s height and weight. It is one of the most widely used figures in health screening, and also one of the most widely misunderstood. BMI can be a useful quick indicator at the population level, but on its own it cannot tell you whether an individual person is healthy. This guide explains what BMI is, how it is calculated, what the standard categories mean, and the real limits of what the number can say.

In this guide

What BMI is

BMI is a ratio. It compares a person’s weight to their height and produces one number, which is meant to give a rough sense of whether that weight is high, low, or typical for that height.

It was created in the 1800s by a statistician studying populations, not by a doctor assessing individuals, and that origin matters. BMI was designed to describe groups of people, and it still works best that way. It is one of many figures you can work out with the calculators in our guide to free online calculators, and like any single number, it answers a narrow question.

How BMI is calculated

The formula is simple: weight in kilograms divided by height in metres squared. A person who is 1.75 metres tall and weighs 70 kilograms has a BMI of 70 divided by 1.75 times 1.75, which works out to about 22.9.

The arithmetic is easy to get wrong by hand, mostly because of the squared height, so the BMI calculator does it for you. You enter height and weight, and it returns the figure. The calculation is the easy part. Understanding what the result does and does not mean is what actually matters.

The standard BMI categories

Health organisations group adult BMI values into broad bands. The widely used ranges are below 18.5, from 18.5 to 24.9, from 25 to 29.9, and 30 and above.

It is important to read these as population statistics rather than as a verdict on any one person. The bands describe where health risk tends to shift across large groups. They do not account for an individual’s build, muscle, age, or background, and a number falling near a boundary says very little on its own. The categories are a starting point for a conversation, not a conclusion.

BMI has lasted for a reason. It is quick, it is free, it needs no equipment beyond a scale and a height measurement, and anyone can work it out. For tracking trends across a large population, or as one quick screening figure among several, it does a reasonable job.

It can also be a rough personal reference point over time. A clear, sustained change in BMI can be a prompt to look more closely at the fuller picture with a professional. As a flag, it has some value. As a final answer, it does not.

What BMI cannot tell you

This is the part most often missed. BMI uses only height and weight, so everything those two numbers leave out is invisible to it.

It cannot tell muscle from fat. Muscle is denser than fat, so a person who trains regularly can weigh more and land in a higher BMI band while carrying very little body fat. The number reads the weight, not what the weight is made of.

It cannot see where fat sits. Fat carried around the abdomen is linked to more health risk than fat carried elsewhere, but BMI produces the same figure either way. A simple waist measurement often tells a doctor more.

It fits some groups better than others. BMI was derived mainly from one population, and research shows the same BMI value can carry different health meaning across different ethnic backgrounds. It is not equally calibrated for everyone.

It does not account for age or life stage. Body composition shifts across a lifetime. Older adults naturally lose muscle, and BMI cannot reflect that change.

A screening number, not a diagnosis

The most accurate way to think about BMI is as one screening figure, never a diagnosis. A healthcare professional uses it alongside many other things: blood pressure, blood tests, a waist measurement, family history, activity, and how a person actually feels day to day. The BMI number contributes to that picture. It does not stand in for it.

If you have questions about your own health, a BMI figure is not the place to find the answer. A healthcare professional who can look at the whole picture is, and they can give context that no single number can.

Tool used in this guide

Frequently asked questions

How is BMI calculated?

BMI is weight in kilograms divided by height in metres squared. The BMI calculator does the arithmetic for you once you enter height and weight.

What counts as a normal BMI?

The standard adult range used by health organisations is 18.5 to 24.9. This is a population guideline, not a judgement on any individual, and it does not account for build, muscle, or age.

Is BMI an accurate measure of health?

BMI is a useful quick screen but a limited one. It cannot distinguish muscle from fat, cannot show where fat is carried, and is not equally calibrated for every group.

Why does my BMI not seem to match how I feel?

BMI uses only height and weight. It does not account for muscle, body composition, age, or build, so it can read as misleading for athletic or very muscular people, among others.

Should I be concerned about my BMI?

BMI is one screening number, not a diagnosis. Any concerns about your health are best discussed with a healthcare professional who can consider the full picture rather than a single figure.

Free Online Calculators: Math, Numbers and Everyday Tools

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Free online calculators handle the kind of arithmetic that is slow, error-prone, or simply tedious to do by hand. Finding every prime factor of a large number, working out the 40th Fibonacci number, or checking a body mass index takes seconds with the right tool and several careful minutes without one. This guide is a map of the calculators on this site: the number and math tools, the sequence and constant tools, and the everyday calculators, with a note on when each one earns its place.

In this guide

When a calculator beats doing it by hand

Some arithmetic is quick in your head. Some is not. The work that genuinely needs a tool tends to share three traits: it repeats the same step many times, a single slip ruins the whole answer, or the numbers are simply too large to track.

Finding the prime factors of 4,294,967,295 is not hard in principle, it is just dozens of trial divisions where one mistake sends you down the wrong path. A calculator removes that risk. The tools below all run in your browser, process the numbers on your own device, and need no account, so reaching for one costs nothing.

Number and digit calculators

The most basic calculators work on the digits and structure of a number. The digit sum calculator adds up the individual digits of a number, a step used in checksums and in simple divisibility tests. The digit product calculator multiplies them instead.

For working across a whole set of numbers, the number sum calculator and the sum of integers calculator total a list or a range, and the number divisors calculator lists every number that divides cleanly into a given value.

Prime and factor calculators

Prime numbers are the building blocks of every other whole number, and they are tedious to work out by hand. The prime numbers calculator lists the primes up to a limit you set. The prime factors calculator breaks a single number down into the primes that multiply to make it, for example showing that 360 is 2 by 2 by 2 by 3 by 3 by 5.

Prime factorisation sits behind a lot of practical maths, from simplifying fractions to the key exchange that protects web traffic, so a reliable tool for it is worth keeping handy.

Sequence calculators

A sequence is a list of numbers built by a fixed rule, and the famous ones grow fast enough that hand calculation becomes impractical within a dozen steps. The Fibonacci calculator generates the sequence where each number is the sum of the two before it, the pattern that appears throughout nature and design.

The Lucas numbers calculator handles a closely related sequence, and the factorial calculator works out factorials, the running product 1 by 2 by 3 and onward, which grow so quickly that 20 factorial already passes two quintillion.

Math constant calculators

Some numbers never end and never repeat, and you sometimes need them to a specific precision. The pi digits calculator produces the digits of pi to as many places as you ask for. The e digits calculator does the same for Euler’s number, the base of natural logarithms, and the phi digits calculator produces the golden ratio. These are useful for testing, for teaching, and for any work that needs a constant carried to high precision.

Everyday calculators

Not every calculator is about pure maths. A few solve common practical problems. The BMI calculator works out body mass index from height and weight, a quick screening figure worth understanding properly, which our guide to BMI covers in full.

The age calculator works out an exact age in years, months, and days from a birth date, and the aspect ratio calculator resizes width and height while keeping their proportion fixed, which is the everyday fix for images and video that would otherwise stretch. The full set lives in the math tools category and the number tools category.

Frequently asked questions

Are these calculators free?

Yes. Every calculator on the site is free, runs in your browser, and needs no account. The numbers are processed on your own device.

What is prime factorisation used for?

It breaks a number into the primes that multiply to make it. It is used to simplify fractions, find common denominators, and it underpins parts of modern encryption.

How large a number can these tools handle?

The calculators handle everyday and large values comfortably. Extremely large inputs, such as a factorial of a very high number, can take longer because the result itself becomes enormous.

What is the difference between digit sum and number sum?

A digit sum adds the individual digits inside one number, so the digit sum of 142 is 7. A number sum adds several separate numbers together.

Why would I need the digits of pi?

Most often for testing, teaching, or any calculation that must carry a constant to a set precision. The pi digits calculator produces as many places as you request.

Base64, Base32 and Base58 Encoding Explained

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Base64 encoding is the reason you can paste an image straight into a CSS file, send a photo as an email attachment, or store a whole file inside a single line of JSON. It takes raw binary data and rewrites it using only plain text characters that survive being sent anywhere. This guide explains Base64 encoding and its two relatives, Base32 and Base58: what each one does, where you will meet it, and how to encode and decode it.

In this guide

What base encoding actually means

Base encoding is often confused with number systems, but the two solve different problems. Number systems, the binary and hexadecimal covered in our guide to number systems, are about how to write a single value. Base encoding is about packaging arbitrary binary data, an image, a document, any bytes at all, as plain text.

The reason this matters is that many systems only handle text safely. Email, URLs, JSON, and HTML were all built around text, and raw binary data sent through them can be corrupted or rejected. Base encoding solves that by mapping the binary data onto a small, safe set of characters, so it can travel anywhere text can.

Base64: the everyday encoding

Base64 uses 64 characters: the uppercase letters A to Z, the lowercase letters a to z, the digits 0 to 9, and the two symbols plus and slash. Every three bytes of original data are rewritten as four of these text characters.

That four-for-three ratio means Base64 text is about 33 percent larger than the data it represents. The extra size is the price of safety, and for most uses it is a fair trade. If you see an = sign at the end of a Base64 string, that is padding, added so the encoded length comes out as a clean multiple of four characters.

What Base64 is used for

Base64 appears wherever binary data has to ride inside something built for text. Email attachments are encoded with Base64 under the MIME standard. A data URL embeds an image directly into HTML or CSS as a Base64 string, so the page carries the image with no separate file. JSON payloads use Base64 to carry a file inside a text field. The middle section of a JWT authentication token is Base64. In each case, the job is the same: move binary data through a text-only channel.

Base32: encoding that survives case changes

Base32 uses a smaller set, just 32 characters: the uppercase letters A to Z and the digits 2 to 7. Using fewer characters makes the encoded text bulkier than Base64, so why choose it?

Because Base32 survives systems that do not preserve letter case or that get confused by mixed case. The everyday example is two-factor authentication. The secret key behind a code-generating authenticator app is Base32, because that key must be typed or scanned reliably across many devices and systems. Base32 trades size for that reliability.

Base58: built to avoid lookalike characters

Base58 uses 58 characters. It starts from a Base64-style set and deliberately removes the characters people most often confuse: the digit zero and capital O, capital I and lowercase L, and the plus and slash symbols.

The result is an encoding a person can read aloud or copy by hand with far less chance of an error. That is why Base58 is best known from cryptocurrency, where a Bitcoin address is a Base58 string. When a value will be handled by humans rather than only machines, Base58 reduces costly mistakes.

How to encode and decode

The Base64 encoder and decoder converts text and data in both directions. For the other formats, the Base32 encoder and the Base58 encoder do the same job.

To move between encodings and other representations, the ASCII to Base64 converter encodes plain text, the Base64 to ASCII converter reverses it, and the Base64 to hex converter shows the underlying bytes in hexadecimal. Each tool runs in your browser, processes the data on your own device, and asks for no account.

Base64 is not encryption

This is the single most important point about Base64. Because Base64 text looks scrambled, people assume it hides or protects data. It does not.

Base64 is fully reversible by anyone, with no key and no secret involved. Encoding an API key, a password, or any sensitive value in Base64 gives it zero protection, since anyone can decode it in a single step. Base64 is a transport format, not a security measure. Data that must be kept private needs real encryption, which depends on a secret key. Treat Base64 as a way to move data safely, never as a way to hide it.

Free encoding tools used in this guide

Frequently asked questions

Is Base64 encryption?

No. Base64 is encoding, not encryption. It is fully reversible by anyone with no key, so it provides no security at all.

Why is Base64 data larger than the original?

Base64 rewrites every three bytes as four text characters, so the encoded result is about 33 percent larger than the data it represents.

What is Base32 used for?

Its most visible use is the secret key behind two-factor authentication apps, because Base32 survives systems that do not preserve letter case.

What is Base58 used for?

It is best known from cryptocurrency addresses. Base58 removes characters that look alike, so values are safer to copy by hand.

What does the equals sign at the end of a Base64 string mean?

It is padding. The equals sign is added so the encoded length comes out as a multiple of four characters.

Number Systems Explained: Binary, Hexadecimal, Octal and Decimal

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Number systems are the different ways of writing the same value. The quantity that decimal writes as 255, binary writes as 11111111, and hexadecimal writes as FF. These are not different numbers. They are the same amount in different notation. Computers rely on several of these notations at once, and knowing how they relate explains a great deal of what you see in code, in colour values, and in raw file data. This guide explains the four number systems you will actually meet, decimal, binary, hexadecimal, and octal, and how to convert between them.

In this guide

Why computers use more than one number system

A computer is built from switches, and each switch is either off or on. Those two states are the two digits of binary, 0 and 1, and binary is the only system the hardware truly uses. Everything else exists for the people reading it.

Binary is correct but hard to read. A single byte is eight digits long, and a memory address can run past thirty. Hexadecimal packs that same information into a quarter of the digits, so programmers use hex to read and write what the machine stores as binary. Decimal is the system people count in day to day. Octal is an older shorthand that still appears in a few specific places. Each system carries the same information, written for whoever needs to read it.

Decimal: base 10, the system you already use

Decimal is the system you grew up with. It has ten digits, 0 through 9. Its proper name, base 10, describes the rule behind it: each place is worth ten times the place to its right. In the number 4253, the 3 is worth 3, the 5 is worth 50, the 2 is worth 200, and the 4 is worth 4000.

Nothing about base 10 is special to mathematics. We use it because people have ten fingers. A computer has no fingers, so it has no reason to count in tens, and internally it does not.

Binary: base 2, how computers count

Binary has two digits, 0 and 1, and each digit is called a bit. Each place is worth twice the place to its right: 1, 2, 4, 8, 16, and so on. To read a binary number, add the place values wherever a 1 sits.

The binary number 1101 has a 1 in the 8 place, the 4 place, and the 1 place, so it equals 8 plus 4 plus 1, which is 13 in decimal. Eight bits together make a byte, and one byte can hold any value from 0 to 255. Binary is exact and it matches the hardware directly, but it is long and easy to misread, which is the reason the other systems exist. To turn a binary value into everyday decimal, the binary to decimal converter does it instantly.

Hexadecimal: base 16, binary made readable

Hexadecimal, usually shortened to hex, has sixteen digits. The first ten are 0 through 9, and the next six are the letters A through F, where A stands for 10 and F stands for 15.

Hex matters because of how cleanly it fits binary: one hex digit is exactly four bits. That means a byte, which is eight bits, is always exactly two hex digits. The byte 11111111 is FF, and 00000000 is 00. This is why hex appears everywhere a person needs to read binary data. A colour written as #1D9E75 is three bytes shown as six hex digits, one pair each for red, green, and blue. The binary to hex converter turns a binary value into hex.

Octal: base 8, the older shorthand

Octal has eight digits, 0 through 7. One octal digit is exactly three bits, the same idea as hex but in smaller groups.

Octal was common on older computer systems and is now mostly a niche. It still appears in a few places, the best known being file permissions on Unix and Linux systems, where a permission written as 755 is an octal number. The binary to octal converter handles that conversion. For most modern work, hex has replaced octal.

How to convert between number systems

Converting by hand is straightforward arithmetic, but it is slow and easy to slip on, especially with long values. The practical approach is a converter.

The binary to decimal, binary to hex, and binary to octal converters each take a binary value and return it in the system you need. The full set lives in the binary tools category and the number tools category. Each one runs in your browser with no signup, and the value never leaves your device.

From text to numbers: ASCII and character codes

Number systems explain how a computer stores numbers. Text is stored the same way, also as numbers. Every letter, digit, and symbol is assigned a code by a standard called ASCII. The capital letter A is 65, lowercase a is 97, and the digit 0 is 48. Those codes are then held in binary, so the letter A becomes 01000001.

This is the bridge between the text you type and the bits on disk. The ASCII to binary converter shows a piece of text as its binary codes, the binary to text converter reverses it, and the ASCII to hex converter shows the same text as hex codes.

Bitwise operations: working with bits directly

Sometimes you need to work on the bits themselves rather than the value they represent. Bitwise operations compare two binary numbers one bit at a time. AND returns a 1 only where both inputs have a 1. OR returns a 1 where either input does. XOR returns a 1 where exactly one input does.

These three operations are the building blocks of low-level programming, permission flags, and simple encryption. The binary AND tool performs a bitwise AND on two values, the binary addition tool adds two binary numbers, and the bitwise hex calculator works directly on hexadecimal values.

Special encodings: BCD and Gray code

Two specialised encodings round out the picture. BCD, short for binary coded decimal, stores each decimal digit as its own four-bit group instead of converting the whole number at once. It is used where a value must map cleanly back to separate decimal digits, such as some clocks and numeric displays. The BCD to decimal converter handles it.

Gray code is a binary sequence arranged so that any two consecutive values differ by only one bit. That property prevents read errors in hardware like rotary encoders, where several bits changing at once could be misread. The binary to Gray code converter produces it.

Quick reference

SystemBaseDigitsOne digit equalsCommon use
Decimal100 to 9n/aEveryday counting
Binary20 and 11 bitHow hardware stores everything
Octal80 to 73 bitsUnix file permissions
Hexadecimal160 to 9, A to F4 bitsColours, memory, byte data

Free number tools used in this guide

Frequently asked questions

Why do computers use binary?

Computer hardware is built from switches that are either off or on. Those two states map directly onto the two binary digits, 0 and 1, so binary is the natural system for the machine.

What is hexadecimal used for?

Hex is a short, readable way to write binary. One hex digit equals exactly four bits, which makes it ideal for colour codes, memory addresses, and raw byte data.

Is binary 1101 the same as decimal 1101?

No. Binary 1101 equals decimal 13. The same digits represent different values depending on the base they are written in.

What is a byte?

A byte is a group of eight bits. It can hold any value from 0 to 255, which is exactly two hexadecimal digits.

Where is octal still used?

The most common place is Unix and Linux file permissions, where a setting such as 755 is an octal number.

The GIF Format Explained: Animation, Limits, and When to Use It

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The GIF format is the oldest image format still in everyday use, and it has survived for one reason: animation. A GIF can hold a short looping clip that plays anywhere, with no video player and no sound. That single trick kept GIF alive for more than thirty years. But the format also carries hard limits that make it the wrong choice for many jobs people still use it for. This guide explains what the GIF format is, where it works, where it does not, and how to work with GIF files.

In this guide

What the GIF format is

GIF, short for Graphics Interchange Format, dates from 1987. It stores an image, or a sequence of images, as a grid of pixels, and it is lossless, so it does not blur or smear the way a heavily compressed JPG can. The file extension is .gif.

Its standout feature is animation. A single GIF file can contain many frames and a timing instruction, so it plays as a short loop on its own. It is one of the formats covered in our wider guide to image file formats, and it is the only old format that handles motion.

The 256 colour limit

GIF has one limit that shapes everything else: a single GIF can contain at most 256 colours. A modern photo holds millions. When a photographic image is forced into 256 colours, smooth gradients break into visible bands, and the picture takes on a blotchy, posterised look.

This is why GIF works for a flat-colour logo animation or a simple icon, where 256 colours is plenty, and fails for a video clip or a photographic animation, where it looks rough and the file still ends up large. The colour limit is not a bug to work around. It is the line between what GIF does well and what it does badly.

Animated GIFs and what they cost

An animated GIF is convenient because it plays everywhere with no effort. The cost is weight. Because GIF compresses poorly compared with modern formats, a few seconds of animation can produce a file of several megabytes.

Picture a short five second product animation. As a GIF it might land near 4 MB, enough to slow a page noticeably on a phone. The same clip in a modern format can drop below 1 MB and look better doing it. On a busy page, a single heavy GIF can outweigh every other image combined.

GIF vs WebP vs MP4 for animation

For animation on your own website, GIF is rarely the best option today. Two alternatives beat it.

An animated WebP keeps full colour and compresses far better, so it looks sharper and weighs a fraction of a GIF. A short MP4 video is smaller still and is the right choice for anything longer or more detailed. GIF holds on mainly because some chat apps, messaging platforms, and older systems expect it specifically. When a platform asks for a GIF, give it one. When you control the page, reach for WebP or MP4 instead.

How to extract frames from a GIF

Sometimes you do not want the animation, you want one picture out of it: a single clean frame to use as a thumbnail, to edit, or to check a detail. The GIF frame capture tool separates an animated GIF into its individual frames so you can save the exact one you need.

It runs in your browser, processes the file on your own device, and asks for no account. Drop the GIF in, and every frame is laid out for you to pick from.

How to confirm a file is a GIF

A file named clip.gif is not always a GIF. Files get renamed and re-saved, and the extension can describe something the data is not, which causes uploads and editors to fail.

The GIF format checker reads the real file data and tells you whether the file is genuinely a GIF. If you need to produce a GIF from a bitmap image, the BMP to GIF converter handles that conversion.

When GIF is still the right choice

GIF earns its place in a few specific cases. Use it for a simple, flat-colour animation, such as an animated icon or a short looping graphic with few colours. Use it when a platform or piece of software explicitly requires a GIF and will not accept WebP or MP4. And use it for a tiny looping clip where guaranteed compatibility matters more than file size.

For anything photographic, anything longer than a few seconds, or anything on a page where speed matters, a modern format will serve you better.

Free GIF tools used in this guide

Frequently asked questions

Why do GIF files look grainy?

A GIF can hold only 256 colours. When a photographic image is forced into that limit, smooth gradients break into visible bands and the picture looks blotchy.

Why is my GIF file so large?

GIF compresses poorly compared with modern formats. A few seconds of animation can produce a file of several megabytes, where an animated WebP or MP4 of the same clip would be much smaller.

Should I use GIF or WebP for animation?

For your own website, WebP. An animated WebP keeps full colour, looks sharper, and weighs far less. Use GIF only when a platform specifically requires it.

Can I get a still image out of an animated GIF?

Yes. The GIF frame capture tool separates a GIF into its individual frames so you can save the exact one you want.

Does GIF lose quality like JPG?

No. GIF is lossless, so it does not blur or smear. Its weakness is the 256 colour limit, not lossy compression.

BMP Files: What They Are and How to Convert Them Free

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BMP files have one defining trait: they are huge. A 1920 by 1080 image saved as a BMP weighs around 6 MB. The same picture as a JPG drops to roughly 300 KB, and as a WebP, closer to 150 KB. That single fact explains almost everything about BMP, where it came from, why it is rarely used today, and why the usual job with a BMP is converting it into something smaller. This guide explains what BMP files are and how to convert them, free and in your browser.

In this guide

What a BMP file is

BMP, short for bitmap, is an image format Microsoft introduced for early versions of Windows. It stores a picture in the most direct way possible: a grid of pixels, with the colour of every single pixel written out in full. The file extension is .bmp.

That direct approach makes BMP simple and reliable. Any program can read it without guesswork. It is one of the formats covered in our wider guide to image file formats, and it sits at the opposite end of the scale from a format like WebP. Where WebP works hard to make files small, BMP does no real compression at all.

Why BMP files are so large

A modern format looks at a photo and finds shortcuts. A stretch of blue sky is thousands of nearly identical pixels, so JPG or WebP store that region compactly instead of repeating the same value over and over. BMP does not look for shortcuts. It writes every pixel at full size, sky and all.

The result is a file 20 to 50 times larger than the same image in a compressed format. A desktop wallpaper that would be 400 KB as a JPG can reach 15 MB or more as a BMP. That weight is the reason you almost never want to keep an image as a BMP, send one by email, or put one on a web page.

Where you still run into BMP files

If BMP is so heavy, why does it still turn up? Because some software never moved on. Older Windows programs, certain scanners, some industrial and medical imaging devices, and a few specialised tools still produce BMP files by default.

So a BMP usually lands on your desk from somewhere else: a scan, an export from a legacy application, a file a colleague sends from an old system. You rarely choose to create one. The task is almost always the same, turn it into a smaller, more portable format.

Which format to convert a BMP to

The right target depends on what the image is and where it is going.

  • PNG if the image is a graphic, a screenshot, or line art, or if it needs a transparent background. PNG is lossless, so sharp edges stay crisp.
  • JPG if the image is a photograph headed for email or the web and you want a small file. JPG compresses photos efficiently.
  • WebP if file size matters most. WebP produces the smallest result of the common formats and works in every current browser.
  • GIF only if a specific platform or piece of software asks for a GIF. It is limited to 256 colours and is rarely the best choice otherwise.

How to convert a BMP file

Pick the converter that matches your target and drop the BMP onto it. Each tool runs in your browser, processes the file on your own device, and asks for no account.

Conversion is a one-way step. The new file is what you will use, but keep the original BMP until you have checked the result looks right, especially if you converted to a lossy format like JPG.

How to confirm a file is really a BMP

A file named scan.bmp is not always a BMP. Files get renamed and re-saved, and the extension can end up describing something the data is not. If a converter rejects your file, a format mismatch is a likely cause.

The BMP format checker reads the actual file data and confirms whether it is genuinely a BMP, so you know which converter you really need before you start.

Quick reference

Your goalConvert BMP to
Keep graphics and edges losslessPNG
Small photo for web or emailJPG or JPEG
Smallest possible web fileWebP
A platform that requires GIFGIF

Frequently asked questions

Why is my BMP file so large?

BMP stores every pixel at full size with no real compression. That makes it 20 to 50 times larger than the same image as a JPG or WebP.

What should I convert a BMP to?

PNG for graphics and transparency, JPG for photographs, WebP for the smallest web file. GIF only if a platform specifically requires it.

Does converting a BMP lose quality?

Converting to PNG keeps every pixel exactly. Converting to JPG or lossy WebP discards a small amount of detail once, in exchange for a much smaller file. The BMP itself loses nothing in the process, so keep the original until you are happy with the result.

Can I open a BMP file without special software?

Yes. Almost every image viewer and browser can open a BMP. The problem is its size, not its compatibility, which is why converting it is usually worthwhile.

Is my file uploaded when I convert it?

No. These converters run inside your browser. The file is processed on your own device and is never sent to a server.

How to Blur a License Plate or Face in a Photo (Free, No Upload)

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Blurring a license plate before you post a photo takes about ten seconds, and it is the difference between a clean car listing and handing a stranger your registration details. The same applies to faces in street photos, dashcam clips, and real estate shots. This guide shows how to blur a license plate or a face for free, directly in your browser, with the image never leaving your device.

In this guide

Why blur faces and license plates

A license plate is a public identifier that links a specific car to a registered owner. A face identifies a person directly. When either one appears in a photo you publish, you are sharing personal information about someone, sometimes yourself, sometimes a stranger who never agreed to it.

The situations where this matters are everyday ones. You photograph your car to sell it on a marketplace, and the plate is sitting in the frame. You post a street photo to a blog, and two passersby are clearly recognisable. You share a dashcam clip, and every car around you is identifiable. Some platforms now require plates and faces to be blurred before a listing goes live, and in many places privacy law treats the face or plate of an uninvolved person as personal data you are not free to publish.

Blurring is quick, and it removes the risk without ruining the photo.

The free tools you need

Four browser tools cover every case. None of them upload your image to a server, and none ask for an account.

  • The blur license plate tool finds the plate in a photo and blurs it.
  • The blur face tool detects faces and blurs each one.
  • The general blur tool blurs any area you choose, useful for a house number, a name badge, or a reflection that the automatic tools do not catch.
  • The censor tool places a solid black bar over an area when you want it gone completely rather than softened.

How to blur a license plate

Open the blur license plate tool and drop your photo onto it. The tool scans the frame and draws a box around the plate it finds. Check that box: if it sits slightly off, drag it to cover the full plate, and if a second car in the background also has a visible plate, add a box there too.

Set the blur strength. For a plate, use enough that the characters are completely unreadable, not just softened. A faint, lightly blurred plate can still be read at full zoom. Then download. The whole pass takes around ten seconds for one photo.

How to blur a face

The blur face tool works the same way. Drop the photo in, and the detector draws a box around every face it finds.

Always review the boxes before you download. On a busy frame the detector can miss a face in shadow, a partial profile, or a face reflected in a window, and it can occasionally box something round that is not a face at all. Add a box over anything it missed, remove any false positive, then download. For a group photo, this review step is the part that actually protects people, so do not skip it.

Blur or black bar: which to use

Blurring keeps a photo looking natural. The plate or face becomes an unreadable smudge, but the image still reads as a normal photo, which is what you want for a car listing or a social post.

A black bar from the censor tool is the stronger choice. It removes the area completely, with no chance of anything being recovered from it. Use a blur when the goal is a tidy, natural-looking photo, and use a black bar when the information is sensitive and must be entirely gone.

A real example, start to finish

Andreas is selling a 2018 Volkswagen Golf on a car marketplace. He takes eight photos of the car: front, back, sides, interior, and a few details. Three of the eight clearly show the rear plate, and one exterior shot also caught a neighbour standing at a ground-floor window.

He runs the three plate photos through the blur license plate tool, about ten seconds each. The photo with the neighbour goes through the blur face tool. Total time, a little over two minutes. The listing now shows the car honestly, with nothing that identifies Andreas by registration or exposes a neighbour who never agreed to appear in an ad.

Four mistakes to avoid

Blurring too lightly. A weak blur leaves a plate or face partly readable when someone zooms in. Use enough strength that the detail is genuinely gone.

Missing reflections. A plate can appear reflected in a shop window or a car door, and a face can show up in a mirror. The automatic detectors often miss these, so scan the whole frame and use the general blur tool on anything left.

Blurring only the obvious one. A photo of your car in a car park may have three other plates in the background. A street photo may have a second face you did not notice. Check the edges and the background, not just the subject.

Forgetting the hidden location data. Blurring changes what is visible in the photo, but a file from a phone can still carry GPS coordinates in its metadata, recording exactly where the photo was taken. That is separate from anything you can see, and removing it is its own step.

Free privacy tools used in this guide

Frequently asked questions

Is blurring a license plate enough for privacy?

For casual posting, a strong blur is usually enough. If the photo is sensitive, a solid black bar from the censor tool removes the plate completely and is the safer choice.

Can a blurred plate be read again later?

A light, weak blur can sometimes be partly recovered. A strong blur, or a black bar, cannot. When in doubt, blur harder or use a black bar.

Does my photo get uploaded anywhere?

No. These tools run inside your browser. The image is processed on your own device and is never sent to a server, and there is no sign-up.

Do I need to blur faces in my own photos?

Your own face is your choice. The concern is the face of another person who appears in your photo and did not agree to be published, such as a passerby or a neighbour.

Does blurring remove the location data from a photo?

No. Blurring changes the visible image only. A phone photo can still carry GPS coordinates in its metadata, and removing that is a separate step.

WebP Format Explained: Why It Is the Best Image Format for the Web

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WebP format is Google’s answer to a simple problem: images on the web are too heavy. A WebP file is usually 25 to 35 percent smaller than the same photo as JPG, and smaller than PNG for graphics, with no visible drop in quality. This article explains what the WebP format is, why Google built it, how it compares to JPG and PNG, when to use it, and how to check, compress, and edit WebP files. It goes deeper on one format from our wider guide to image file formats.

In this guide

What the WebP format is

WebP is an image format Google released in 2010 and has refined ever since. It is designed for one job: showing images on web pages using as few bytes as possible. The file extension is .webp.

What makes WebP unusual is range. JPG handles photographs but cannot do transparency. PNG handles graphics and transparency but produces large files. GIF handles animation but only 256 colours. WebP does all of it: photographs, graphics, transparency, and animation, in a single format. That is why it has become the default recommendation for web images.

Why Google created WebP

Google measures the web for a living, and one number kept growing: page weight. Images are the largest part of most pages, often more than half the total bytes a visitor downloads. Heavier pages load slower, and slower pages lose visitors and rank lower in search.

JPG and PNG were designed in the early 1990s. They are reliable, but their compression is old. Google built WebP to compress the same image far harder while keeping it looking the same, so a page could carry the same pictures at a fraction of the download cost. For a business, that is faster pages, lower bandwidth bills, and a small but real ranking benefit, since page speed is part of how Google ranks results.

How much smaller WebP files are

The savings are large enough to notice on a real page. Picture an online store with a product gallery of twelve photos, each one an 800 KB JPG. That gallery is 9.6 MB. Re-saved as WebP at the same visible quality, the same twelve images land near 3 MB. The page that took eight seconds on a phone now takes under three.

As a rough guide, expect a WebP file to be 25 to 35 percent smaller than the equivalent JPG, and around 26 percent smaller than a PNG for the same graphic. The exact figure depends on the image, but WebP wins almost every time.

WebP does both lossy and lossless

Most formats pick a side. JPG is always lossy, it throws away detail to shrink the file. PNG is always lossless, it keeps every pixel and stays larger. WebP offers both modes in one format.

Lossy WebP is the choice for photographs, where discarding a little invisible detail is a fair trade for a much smaller file. Lossless WebP is the choice for logos, screenshots, and flat-colour graphics, where sharp edges must stay crisp. You pick the mode that matches the image, and in both cases the result is smaller than the older format it replaces.

Transparency: WebP vs PNG

Transparency is the see-through background that lets a logo sit cleanly on any colour. For years PNG was the only practical way to get it. WebP supports transparency too, and it does so at a much smaller size.

A transparent logo that is 180 KB as a PNG is often near 60 KB as a WebP, with the edges just as clean. If a site uses transparent graphics in its header, footer, and product images, switching them to WebP trims real weight from every page without any visible change.

Animation: WebP vs GIF

WebP can also hold short animations, the same looping clips GIF is known for. The difference is quality and size. GIF is locked to 256 colours, so a photographic animation looks blotchy, and GIF files are large. Animated WebP keeps full colour and compresses far better.

A short product animation that is 4 MB as a GIF can drop below 1 MB as an animated WebP, and it will look better doing it. GIF still has a place where a platform specifically expects it, but for animation on your own site, WebP is the lighter choice.

Browser support: is WebP safe to use

This used to be the reason people hesitated, and it no longer applies. Every major browser, Chrome, Firefox, Safari, and Edge, has supported WebP since 2020. In practice that covers almost every visitor who will reach your site today.

You can use WebP as your default web image format with confidence. The old advice to keep a JPG fallback is now only relevant if you must support browsers that are many years out of date.

When not to use WebP

WebP is the right default for the web, but it is not the right format everywhere. Three cases call for something else.

For images that will be printed or sent to a print shop, stick with the format the printer asks for, usually a high-quality JPG or TIFF. For a logo that must scale to any size, from a favicon to a banner, a vector SVG stays sharp where any pixel format, WebP included, would blur. And for a file you are handing to someone on much older software, a plain JPG or PNG removes any risk that their program cannot open it.

How to check if a file is WebP

A file named image.jpg is not always a JPG. Files get renamed, downloaded, and re-saved, and the extension can end up describing something the data is not. When an upload fails or an editor rejects a file, a format mismatch is a common cause.

The reliable way to know is to read the file data itself. The WebP format checker confirms in one step whether a file really is WebP. For a closer look at a WebP file, its dimensions, whether it uses lossy or lossless mode, and whether it has transparency, the WebP analyzer reports the details.

How to compress and optimise WebP

WebP is already efficient, but a WebP file straight out of an export is rarely as small as it could be. Two tools tighten it further.

The WebP compressor shrinks a WebP file while keeping it usable, which is the quick option when you just need a lighter file. The change WebP quality tool gives you precise control, letting you set the exact quality level and watch the size change, so you can find the point where the file is small but still looks right. If you are pulling a WebP out of code or a data string, the Base64 to WebP converter turns an encoded string back into a real file.

How to edit a WebP file

You do not need to convert a WebP back to another format just to make a small edit. Several tools work on WebP files directly. The blur WebP tool softens a file or part of it, the change WebP color tool adjusts its colour, and the change WebP opacity tool makes the whole image more or less transparent.

All of these run in the browser. The file is processed on your own device, nothing is uploaded to a server, and there is no sign-up. If you have a BMP that needs to become a WebP, the BMP to WebP converter handles that, and the full set lives in the WebP tools category.

Free WebP tools used in this guide

Frequently asked questions

Is WebP better than JPG?

For the web, yes. A WebP file is usually 25 to 35 percent smaller than the same JPG at the same visible quality, and it can also do transparency and animation, which JPG cannot. For print or for very old software, a JPG is still the safer choice.

Do all browsers support WebP?

Every major browser, Chrome, Firefox, Safari, and Edge, has supported WebP since 2020. It is safe to use as a default web image format today.

Does WebP lose quality?

It depends on the mode. Lossy WebP discards a small amount of detail to save space, like JPG. Lossless WebP keeps every pixel, like PNG. You choose the mode that suits the image.

Can WebP have a transparent background?

Yes. WebP supports transparency, and a transparent WebP is usually much smaller than the same image as a transparent PNG.

How do I know if a file is really WebP?

Do not trust the file extension, since it can be renamed. Use a checker that reads the file data, such as the WebP format checker linked above.

The Ultimate Guide to Image File Formats: PNG, JPG, WebP, AVIF and More

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Image file formats are the difference between a web page that loads in two seconds and one that takes eight. A 4.2 MB hero image can add six seconds on mobile data, and the fix is rarely a faster server, it is usually a different format. The format you pick decides three things at once: how large the file is, how sharp it looks, and where it will open. This guide explains the main image file formats, when to use each one, how to identify what you already have, and how to convert between them without losing quality.

In this guide

Lossy vs lossless: the core idea

Every image format is either lossy or lossless, and that single property predicts most of its behaviour.

Lossy formats throw away data to shrink the file. JPG is the classic example. Each time you save a JPG, the format discards detail the human eye is unlikely to notice. The file gets small, but the loss is permanent. Save the same JPG ten times and you can watch it degrade.

Lossless formats keep every pixel exactly. PNG is the common example. A screenshot saved as PNG looks identical to the original, and you can edit and resave it without decay. The trade is size: lossless files are usually larger.

The practical rule: photographs tolerate lossy compression well, because their detail is noisy and irregular. Graphics with flat colour, sharp edges, or text (logos, screenshots, charts) suffer visibly under lossy compression, so they want lossless.

JPG: built for photographs

JPG (also written JPEG) has been the default photo format since the 1990s. It compresses photographs efficiently and opens on every device, browser, and printer made in the last 25 years.

Reach for JPG when the image is a photograph and you do not need transparency. A travel photo, a product shot on a white background, a portrait: all of these are good JPG candidates. A typical 12-megapixel photo that is 6 MB as a camera file drops to roughly 1.5 MB as a quality-80 JPG with no obvious difference.

Avoid JPG for screenshots, logos, line art, or anything with text. The lossy compression smears the sharp edges and leaves grey fuzz around letters. Avoid it too for any image that needs a transparent background, because JPG cannot store transparency at all.

PNG: graphics and transparency

PNG is lossless, so it keeps sharp edges crisp and supports a transparent background. That makes it the right choice for logos, icons, screenshots, charts, and any graphic you plan to place on top of another image or a coloured page.

If a designer hands you a logo that must sit on both a white header and a dark footer, it needs a transparent background, and PNG delivers that. Not sure whether a file actually has transparency? The image transparency checker tells you in one step, which saves the surprise of a white box appearing behind your logo.

The cost of PNG is size. A full-screen photograph saved as PNG can be five to ten times larger than the same photo as JPG. Use PNG for graphics, not for photos.

WebP: the modern web default

WebP is a format Google released specifically to make web pages lighter. It does something the older formats cannot: it offers both a lossy mode and a lossless mode, and it supports transparency and animation. In practice a WebP file is usually 25 to 35 percent smaller than the equivalent JPG, and smaller than PNG for the same graphic.

For a website, WebP is now the sensible default. A 4.2 MB PNG hero image re-saved as WebP would land near 600 KB with no visible loss, turning a six-second mobile load into well under two seconds. Every current browser supports WebP, so the old compatibility worry no longer applies.

The site has a dedicated WebP tools category for working with the format, and you can confirm whether a file is already WebP with the WebP format checker.

GIF: animation and its limits

GIF is old, and it shows. Its headline feature is animation, short looping clips with no sound. Its hard limit is colour: a GIF can hold only 256 colours total. That is fine for a simple animated icon or a flat-colour loop, but a photographic animation turns blotchy and the file balloons in size.

For a short animation today, an animated WebP or a small MP4 video will look better and weigh far less than a GIF. GIF still matters because some platforms and chat apps expect it. If you need to pull the individual frames out of a GIF, for example to edit one frame, the GIF frame capture tool separates them for you.

BMP: uncompressed and oversized

BMP stores an image with little or no compression. Every pixel is written out in full, so a BMP of a photo can be 20 to 50 times larger than the same photo as JPG. A simple desktop wallpaper can reach 25 MB as a BMP.

You almost never want to publish a BMP. It exists mostly because older Windows software, some scanners, and certain industrial and medical devices still produce it. When a BMP lands on your desk, the job is usually to convert it into something smaller and more portable:

You can confirm a file really is a BMP first with the BMP format checker.

AVIF: next-generation compression

AVIF is the newest mainstream format. It compresses harder than WebP, often producing a file 50 percent smaller than JPG at the same visible quality, and it handles a wider range of colour. For a photo-heavy page where every kilobyte counts, AVIF is the strongest option available today.

The trade is maturity. Browser support is good but slightly behind WebP, and encoding an AVIF takes longer. A common professional approach is to serve AVIF to browsers that accept it and fall back to WebP for the rest. If you are choosing one safe format for a site right now, WebP is still the easier call. If you are optimising aggressively and can manage a fallback, AVIF wins on size.

SVG: graphics that never blur

Every format above stores an image as a grid of pixels. SVG does not. It stores a set of drawing instructions: lines, curves, and shapes described by maths. Because it is instructions rather than pixels, an SVG scales to any size with zero blur. The same logo file looks razor sharp on a phone icon and on a billboard.

SVG is the right choice for logos, icons, and simple illustrations with flat colour. It is the wrong choice for photographs, which have no clean shapes to describe and would produce a huge, useless file. The quick test: if you could draw it with a pen in clean lines, SVG suits it. If it is a photo, it does not.

HEIC: the iPhone format

Recent iPhones save photos as HEIC by default. HEIC compresses better than JPG, so the photo takes less space on the phone. The friction starts when you move that file somewhere else: many Windows programs, older software, and some websites will not open a HEIC file.

If someone emails you a HEIC photo and your software refuses it, the file is fine, it just needs converting to a format the receiving program understands, usually JPG for a photo or PNG if you need transparency.

How to tell what format you have

A file extension can lie. Someone renames photo.webp to photo.jpg and now the name says one thing while the actual data says another. That mismatch causes uploads to fail and editors to throw errors. The reliable way to know is to inspect the file data itself, not the name.

Each of these checkers reads the real file signature and tells you the truth:

How to convert and shrink images

Once you know what you have and what you need, two jobs cover most cases: converting the format and reducing the size.

For converting, pick the tool that matches your starting format and target, such as the BMP converters listed above. For reducing size without changing format, the image compressor shrinks a file while keeping it usable, and the change image quality tool lets you trade a precise amount of quality for a smaller file. If you work with images embedded in code or data, the Base64 to image converter turns an encoded string back into a real file.

Every one of these runs in the browser. The image is processed on your own device, nothing is uploaded to a server, and there is no sign-up. The full set lives in the image tools category.

Free image tools used in this guide

Quick reference table

FormatTypeTransparencyAnimationBest for
JPGLossyNoNoPhotographs
PNGLosslessYesNoGraphics, screenshots, logos
WebPBothYesYesThe web, as a default
AVIFBothYesYesAggressive web optimisation
GIFLosslessYesYesSimple flat-colour animation
BMPUncompressedNoNoLegacy software output
SVGVectorYesYesLogos, icons, illustrations
HEICLossyNoNoiPhone photo storage

Frequently asked questions

Which image format is best for a website?

WebP, as a default. It is smaller than JPG and PNG, supports transparency and animation, and works in every current browser. Use AVIF if you are optimising hard and can set up a fallback.

Should I use JPG or PNG for a photo?

JPG. It compresses photographs far smaller with no visible loss. Keep PNG for graphics, screenshots, and anything that needs transparency.

Does converting between formats lose quality?

Converting into a lossless format (PNG, BMP) keeps everything. Converting into a lossy format (JPG, WebP lossy) discards some detail once. Converting a JPG to PNG will not restore detail the JPG already removed.

Why will my HEIC file not open?

The file is valid, but many non-Apple programs do not read HEIC. Convert it to JPG or PNG and it will open anywhere.

How do I know a file’s real format?

Do not trust the extension, since it can be renamed. Use a checker that reads the file data, such as the format checkers linked above.