Binary Converter
Text to binary and back, or decimal to binary — 8-bit bytes, exact big-integer math.
Result
About this tool
Binary is the bottom layer: every file, character and number in every computer is ultimately a sequence of bits. Converting between binary and readable forms is partly practical (debugging bitmasks, reading protocol dumps, checking how text encodes) and partly educational — watching "Hi" become 01001000 01101001 makes the abstraction concrete in a way no explanation matches.
Text mode converts any string to its UTF-8 bytes as space-separated 8-bit groups, and decodes binary back to text. The decoder ignores spacing entirely and validates honestly: if the bit count isn't a multiple of 8, it tells you exactly that instead of producing garbage — the most common paste error, caught with a clear message. ASCII characters take one byte; accented characters and emoji take two to four, which the output makes visible.
Number mode converts decimal to binary and back, live, editing either field — and like this site's hex converter, it runs on big-integer arithmetic, so values of any length convert exactly where float-based converters silently round. Popular uses: computer science homework, understanding subnet masks and file permissions, binary-themed puzzles and geocaching, and the occasional binary birthday message for a programmer friend. All in your browser, instantly.
How to use the Binary Converter
- 1Pick a mode: Text ↔ Binary for strings, Number ↔ Binary for values.
- 2In text mode, choose direction and paste — spacing in binary input is ignored.
- 3In number mode, edit either field; the other converts live.
- 4Copy the result.
Frequently asked questions
Why is each character 8 digits?
Text encodes as bytes, and a byte is 8 bits — so every character (or part of a multi-byte character) is a group of eight 0s and 1s. The leading zeros matter: 01001000 is 'H', but drop the pad and the grouping breaks.
Why did my binary fail to decode?
Almost always a bit count that isn't a multiple of 8 — a digit lost or added in copying. The tool reports the exact count so you can spot it. Also check that only 0s, 1s and spaces are present.
How do emoji look in binary?
Big — an emoji is typically 4 bytes in UTF-8, so 32 bits. Convert 👍 and you get four 8-bit groups. It's a vivid demonstration of why 'characters' and 'bytes' aren't the same thing.
How does decimal-to-binary conversion work?
Repeated division by 2, collecting remainders — 10 becomes 1010. This tool automates it with exact big-integer math, so even enormous values convert without the rounding errors float-based converters introduce.
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