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Number Base Converter
Type a number in any base and see it written in all the others at the same time. Handy for reading colour codes, permission bits, memory addresses and anything that arrives in hexadecimal.
How to use it
- Type the number.
- Tell the tool which base it is written in.
- Read the decimal, binary, octal, hexadecimal and base-36 forms.
Examples
- 255 → 11111111 in binary, FF in hex.
- hex 1A2B → 6699 in decimal.
- File permission octal 755 → 111101101, the nine permission bits.
Questions people ask
Why do programmers use hexadecimal?
One hex digit stands for exactly four binary digits, so a byte fits in two characters. That makes long binary values readable without changing what they mean, which is why colours, memory addresses and hashes are written that way.
Can I paste prefixes like 0x or 0b?
Yes. A leading 0x, 0b or 0o is stripped automatically, so values copied from source code or a debugger work without editing.
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Updated: 2026-08-07