Base Converter
Convert numbers between binary, octal, decimal, hexadecimal and any base from 2 to 36.
| Binary (2) | 11111111 |
|---|---|
| Octal (8) | 377 |
| Decimal (10) | 255 |
| Hexadecimal (16) | FF |
What is it
A number base (or radix) is how many digits a positional numeral system uses before it carries over. We count in base 10, computers think in base 2, and hex (base 16) is a compact shorthand programmers love. This tool converts an integer between any two bases from 2 to 36, using digits 0-9 then letters a-z.
Notes & fun facts
A quick mental shortcut: every base is just “how many fingers the counting system uses”. Octal (8) and hex (16) both divide neatly into powers of two — that’s why early programmers adopted them: three bits make one octal digit, four bits make one hex digit. Fun trick: “FFF” in hex is 4095 in decimal, exactly 2¹²−1, the max of a 12-bit value.
Origin & history
The Babylonians used base 60 (sexagesimal) with cuneiform as early as 2000 BC — we still feel it in 60-minute hours. Our decimal system came from Hindu-Arabic numerals via the Islamic world around the 8th-10th centuries. Binary was first described by Thomas Harriot around 1600 and formalised by Gottfried Leibniz in 1703, who saw it as the language of the universe. Octadecimal and hexadecimal became standard in the 1950s-60s as computers made binary math practical.