Convert ASCII to Binary
Convert text to 8-bit binary - strict ASCII, byte, or UTF-8 mode, with choice of separator. Free, client-side, instant, offline, secure.
Encode text to 8-bit binary groups. Pick strict ASCII (0–127), extended byte (0–255), or UTF-8 (correct for every Unicode character including emoji), and choose how the bytes are separated.
How to Use Convert ASCII to Binary
- Type or paste text into the input - ASCII, Latin characters, CJK, and emoji are all accepted. The output recomputes within 150 ms of your last keystroke.
- Choose an encoding mode. UTF-8 bytes (default) fits any Unicode character and matches how computers actually store text on disk. Strict ASCII enforces the 7-bit range and flags non-ASCII characters as skipped. Extended byte covers Latin-1 (0-255) and skips anything higher.
- Pick a separator. A single space is the readable default, newline puts each byte on its own line, comma + space suits CSV pastes, and "None" produces a single continuous bit string for regex or shift-register tests.
- Read the stats line: mode, character count, byte count, total bit count, and - when relevant - how many characters were skipped because they fell outside the selected mode's range.
- Watch for the inline warning. In ASCII or byte mode, characters above the mode's limit (e.g.
éin ASCII mode) are listed in the warning bar so you can switch to UTF-8 or rewrite the input. - Copy writes the binary to the clipboard. Download .txt saves a timestamped file named
binary-<mode>-<iso>.txt. Clear wipes everything, Reset options restores mode and separator defaults. - Press
Ctrl+Enter(⌘+Enteron Mac) to encode and copy in a single shortcut - handy when experimenting with different modes or separators.
Frequently asked questions
How does ASCII to binary conversion work?
Each ASCII character has a numeric code point from 0 to 127. The tool prints that code point as an 8-bit binary number, zero-padded from the left. A has code 65 and becomes 01000001; a has code 97 and becomes 01100001.
Is my text data safe?
Yes. Encoding runs entirely in your browser – nothing is uploaded, cached, or tracked. After the page loads you can disconnect the network and keep encoding indefinitely.
What happens with non-ASCII characters like é or 中?
In UTF-8 mode (the default) they encode to multiple 8-bit groups – é is 11000011 10101001 and 中 is three bytes. In Strict ASCII mode they are skipped and counted in the stats line; in Extended byte mode, characters up to ÿ (255) still fit but anything higher is skipped.
Can I convert entire paragraphs?
Yes. The tool handles any reasonable length in real time – tens of thousands of characters finish in under 50 ms on a modern laptop because the underlying pipeline is a single Array.from + toString(2) pass.
Why would I need ASCII to binary?
To learn how text is stored at the bit level, to debug network or serial-protocol dumps, to craft fixtures for computer-science coursework, or to build visual demonstrations that show each character as a row of 1s and 0s.
Does it work offline?
Yes. HTML, CSS, and JavaScript are self-contained. Once the page has loaded, you can turn off Wi-Fi and the tool keeps working – useful on air-gapped machines.
Is it free?
Yes, 100% free with no cap on input length or number of encodes. No sign-up, no premium tier, no watermark.
How many bits does each character become?
In Strict ASCII mode, exactly 8 bits (1 byte) per character – every code point 0-127 fits in 7 bits but is padded to 8 for readability. In UTF-8 mode, 1 to 4 bytes (8-32 bits) per character depending on its code point – A is 1 byte, é is 2, 中 is 3, emoji are 4.
Can I convert binary back to ASCII?
Yes. Use the sibling Binary to ASCII converter. Round-trip is exact when both tools are set to the same mode – UTF-8 in, UTF-8 out.
Which browsers work with this tool?
Every modern browser: Chrome, Firefox, Safari, Edge, Opera, plus mobile browsers on iOS and Android. The only requirement is JavaScript and a working TextEncoder, both standard since 2016.