Number base converter
Binary, octal, decimal, hexadecimal — and every base from 2 to 36 at the same time.
Paste 0xFF, 0b1010 or 0o755 and the base is picked up automatically. Underscores, spaces and commas are ignored.
Display options
Integer part is 8 bits wide.
- Binary211111111
- Octal8377
- Decimal10255
- Hexadecimal16ff
Why the width doesn’t matter here
JavaScript numbers carry 53 bits of precision, so the usual way to write this tool —parseInt(value, 16) — is silently wrong on exactly the values people most often convert. A 64-bit hash entered asFFFFFFFFFFFFFFFF comes back as 18446744073709552000 instead of 18446744073709551615: right length, wrong digits, no error.
This page holds integers as arbitrary-precision values and fractions as exact ratios, so nothing is ever routed through a floating-point number. There is no width limit, and a fraction whose expansion doesn’t terminate in the target base — 0.1 decimal in binary, say — is marked approx. rather than quietly truncated.
