Convert number bases
Binary, octal, decimal, hex — any of them to any of them, with the working shown.
Runs on your device
No uploads, ever
Free, no account
How it works
- Type a number
In whichever base you have it — set the input base first.
- All bases update live
Binary, octal, decimal and hex at once, plus a custom base box for base 3, base 32 and the rest.
- Copy in the format you need
Plain, or with 0x/0b prefixes for pasting into code.
Questions people actually ask
Why binary for 255 is long — got a shortcut?
That's what 255 is in binary, and the box shows the nibble grouping (1111 1111) to make it readable. Hex exists precisely because nobody enjoys reading raw binary.
Negative numbers?
The sign is kept on the output; two's-complement representation is a deeper rabbit hole left to your language of choice.