Number base converter
0x2F is 47, and nobody remembers that.
Output
Paste or type above to see the result here.
Your files stay on your device
This tool runs entirely in your browser. What you paste is processed on your device and is never sent to a server, so it is safe to use with tokens, keys and unpublished text.
How it works
- Type the numbers, one per line.
- Choose which base to read them in — or write 0x, 0b or 0o and that decides instead.
- Every common base comes back at once, so there is nothing to convert twice.
- Turn on bytes if you are reading a value out of a memory dump or a protocol.
Frequently asked questions
- Do I have to say which base it is in?
- Only for a bare number. 0x2F, 0b1010 and 0o17 say it themselves and are read that way whatever the setting is, because that is how they arrive — copied out of a debugger, a hex editor or a stack trace.
- Will a 64-bit value survive?
- Yes. The arithmetic is done in arbitrary precision, so 0xFFFFFFFFFFFFFFFF comes back as 18446744073709551615 rather than as the rounded-off number a tool built on JavaScript's ordinary numbers would give you. That rounding is silent, which is what makes it worth avoiding.
- What are the odd bases for?
- Base 32 and base 36 turn up in short identifiers and URL shorteners; base 12 and base 7 turn up in puzzles and homework. The converter goes up to 36, which is as far as digits plus the alphabet reach.
- Can it do fractions?
- No — whole numbers only. A binary fraction is a different question with its own traps, and pretending 0.1 converts cleanly would be the biggest of them.
- Is anything sent to a server?
- No. It runs in your browser, so what you paste stays on your computer.
Related tools
∿ ASCII and Unicode table The code for a character, or the character for a code. ∿ Base64 Convert text to Base64 and back, with correct UTF-8 handling and an optional URL-safe alphabet. # Hash Generator Get the MD5, SHA-1 or SHA-2 digest of any text, computed on your device. ◒ Colour converter HEX, RGB, HSL and CMYK — plus the contrast ratio that decides readability.