Number Base Converter
Type a number in any base and see it instantly in binary, octal, decimal and hexadecimal.
About number bases
Computers use base-2 (binary) and base-16 (hex) while people usually use base-10. Each field below accepts digits valid for its base; edit any one and the others update together.
FAQ
What characters can I use for hex?
Digits 0–9 and letters A–F (case-insensitive).
Handles non-negative whole numbers.
Use the result with confidence
Type into any base
Each field is an input: edit decimal, hexadecimal, octal or binary and the other three update. Enter digits only, without 0x or 0b prefixes. This tool converts nonnegative whole numbers; it does not interpret signed machine words, fractions or text character encodings.
One value, four representations
Decimal 255 is hexadecimal FF, octal 377 and binary 11111111. The hexadecimal digits mean 15 × 16 + 15. Binary has eight set bits, worth 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1. All describe the same quantity.
Watch leading zeroes and invalid digits
Leading zeroes are omitted from converted results, so a required 8-bit display may need padding. Octal cannot contain 8 or 9; binary permits only 0 and 1. Invalid input clears other results. BigInt arithmetic avoids rounding above JavaScript’s normal safe-integer range; inputs are limited to 1,024 digits.
The example changes this calculator’s fields. It does not save or replace a journal or backup.