About this tool
Binary, octal, decimal and hexadecimal are just different ways of writing the same number, but converting between them in your head is easy to get wrong. This converter turns a value in any base from 2 to 36 into all the others at once — perfect for reading a colour hex, decoding a permission bitmask, or checking a hash byte.
It uses arbitrary-precision BigInt, so even numbers far larger than a 64-bit integer convert exactly with no rounding. Type a value, choose its base, and read every representation. It all happens in your browser.
Frequently asked questions
Is my number data uploaded anywhere?
No. All conversion happens in your browser using JavaScript — nothing is sent to a server, so even sensitive values never leave your device.
What number bases does this tool support?
Binary (2), octal (8), decimal (10), and hexadecimal (16) are shown by default, plus any custom base from 2 to 36 using digits 0-9 and letters a-z.
Can it handle numbers larger than 64-bit integers?
Yes. Conversions use JavaScript's BigInt internally, so there's no precision loss even for numbers far beyond what a standard 64-bit integer can hold.
Do I need to strip prefixes like 0x or 0b before pasting a number?
No, common prefixes (0x, 0b, 0o) are stripped automatically, and the converter also accepts a leading minus sign for negative values.
Why does the tool show an error for my input?
It means the value contains a digit that isn't valid in the selected 'from' base — for example, an '8' or '9' when converting from octal, or a letter beyond 'f' when converting from hex.