Binary & Encoding Tools

Encoding tools convert text between the formats APIs, browsers, and databases use, Base64 for JSON payloads, percent-encoding for URL query strings, HTML entities for safe markup, hex and binary for debugging protocol dumps. A backend developer chasing a broken webhook can paste a Base64 response body, decode it to UTF-8, and spot the malformed field in seconds. This category collects 169 free browser-based tools covering every common pair, text ↔ Base64, string ↔ URL-encoded, UTF-8 ↔ hex, decimal ↔ binary. Client-side, no sign-up.
What you can do with Encoding Tools

Encode or decode Base64 payloads when debugging APIs, start with base64-encode-decode, and base64-to-image when the string is a data URI.
Safely embed user text in URLs or HTML, url-encode-decode handles query strings and html-entity-encode-decode escapes <, >, and &.
Convert between number systems, binary-to-decimal, decimal-to-binary, and hex-to-binary cover the three directions most often typed into a console.

Reach for Encoding tools when the job is reshaping the same bytes into a different representation, the data doesn’t change, the envelope does. If the goal is a cryptographic hash or a secure password (one-way transforms that can’t be reversed), Security Tools is closer. If the problem is UTF-8 vs UTF-16 byte order or emoji variation selectors, Unicode Tools handles character-level work.
The Encoding toolkit

Tool
What it does
When to use

Base64 Encode/Decode
Encodes text to Base64 or decodes it back to plain text.
Decoding a webhook response body to read the JSON it wrapped.

URL Encode/Decode
Percent-encodes reserved characters for URLs or reverses the encoding.
Pasting a pre-encoded query string into Postman for a debug run.

HTML Entity Encode/Decode
Converts <, >, &, and quotes to and from their HTML entities.
Embedding user text in an article template without breaking markup.

Image to Base64
Turns a PNG, JPG, or SVG into a Base64 data URI for CSS.
Inlining a 2 KB logo in critical CSS so the first paint ships one fewer request.

Base64 to Image
Renders a Base64 data URI as a downloadable image file.
Pulling a screenshot out of a JSON API response into a PNG.

Binary to Decimal
Converts a binary string to its decimal integer.
Reading the flags field in a hand-written network packet dump.

Decimal to Binary
Converts an integer to its binary representation.
Building a bitmask literal for a hardware register in microcontroller code.

Hex to Binary
Converts hex digits to the equivalent binary string.
Expanding a 0xFE permissions byte into eight flag bits.

Hex to ASCII
Translates hex byte sequences to readable ASCII text.
Reading a hex-dumped string out of a memory buffer log.

ROT13 Encoder
Shifts letters 13 places, the classic spoiler and puzzle cipher.
Obfuscating a movie spoiler in a forum post without real encryption.

Morse Code Translator
Converts between text and Morse, dots, dashes, and letter separators.
Decoding a scout-badge puzzle or an SOS-in-an-image exercise.

Base32 Encoder
Encodes data in Base32, case-insensitive, URL-safe, no padding confusion.
Generating the secret seed for a TOTP authenticator enrollment QR code.

Encoders for web & APIs handle the three transforms every HTTP request touches. base64-encode-decode wraps binary into text, url-encode-decode escapes reserved characters in query strings, and html-entity-encode-decode keeps user text from breaking rendered markup.
Number-system converters translate the same integer between bases. binary-to-decimal and decimal-to-binary are the two most-typed; hex-to-binary and convert-hex-to-ascii handle byte-dump debugging when a flag register or string buffer arrives in hex.
Data URIs & specialty encodings cover the rarer asks. image-to-base64 and base64-to-image move small assets in and out of CSS. base32-encoder is the format TOTP secrets use; rot13-encoder and morse-code-translator cover puzzles.
How to choose the right encoding tool

If the string came from an HTTP body and looks like random letters ending in = → decode it with base64-encode-decode.
If the string contains %20 or %2F sequences → run it through url-encode-decode.
If the payload has &, <, or ' → use html-entity-encode-decode to recover readable text.
If you see a long sequence of 0x-prefixed bytes from a memory dump → paste it into convert-hex-to-ascii.
If a secret needs to enroll a TOTP 2FA app → encode the raw bytes with base32-encoder.

The trade-off that trips people up is reversibility. Encoding is always two-way, the original bytes are recoverable. Hashing and encryption are not. If the input is a password or credit card, Base64 is the wrong pick; anyone can decode it. For one-way transforms, move to Security Tools.
Frequently asked questions
Q: What’s the difference between Base64 and URL encoding?
Base64 turns arbitrary bytes into 64 printable characters (A-Z, a-z, 0-9, +, /) so binary data can travel inside text-only fields like JSON. URL encoding only escapes reserved characters, spaces become %20, slashes %2F, so a string is safe inside a URL. Use base64-encode-decode for binary-in-text and url-encode-decode for query strings.
Q: Is Base64 a form of encryption?
No, Base64 is encoding, not encryption. Anyone can decode a Base64 string with the public alphabet. The point is to make binary data survive text transports, not to hide it. For real secrets, use password hashing or AES, the Security Tools category covers bcrypt, AES, and random password generators.
Q: How big does Base64 make a file?
Base64 grows the payload by roughly 33%, every 3 bytes of input becomes 4 output characters, plus padding. A 300 KB PNG encoded as a data URI lands near 400 KB. Fine for small assets under 4 KB inlined in CSS, painful for photos over 50 KB. image-to-base64 shows the encoded size upfront.
Q: When should I URL-encode vs. HTML-entity-encode?
URL-encode when the string lives in a URL, a query value, path segment, or form body. HTML-entity-encode when it lives in rendered HTML, inside a <p>, attribute, or template. A user comment on a page needs entity escaping so <script> can’t run; a search term in ?q=... needs URL encoding so & doesn’t split the query.
Q: Why does Base64 sometimes end with = or ==?
The = characters are padding. Base64 works in 3-byte input groups; when the input isn’t a multiple of 3, = pads the output to a multiple of 4. URL-safe Base64 (used in JWTs) strips the padding, re-add = until the length divides by 4 if a decoder rejects the string.
Q: Can I decode a string without knowing which encoding it uses?
Usually, yes, by shape. Strings ending in = with only A-Z/a-z/0-9/+// characters are Base64. Strings full of %XX sequences are URL-encoded. Strings with & or &#NNN; are HTML entities. If the first pass returns gibberish, chain, some payloads are Base64 JSON that was URL-encoded.
Related categories
Encoding work usually touches two neighbors. Unicode Tools handle character-level transforms, UTF-8/UTF-16 conversion, combining characters, emoji variation selectors. Text Tools cover case conversion, slugification, and diffs once the decoded payload is plain text again. For one-way hashing and encryption, Security Tools is the right stop.