Number Base Converter (Binary / Hex / Octal / Decimal)

Convert numbers between any base online

Type a number, choose its source base, and the converted result appears immediately — no button press needed. The tool supports any base from 2 to 36, covering the most common cases: binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). All processing runs locally in your browser; nothing is sent to a server.

The "all bases" panel beneath the main converter shows the same value in binary, octal, decimal, and hex simultaneously, so you can cross-check representations at a glance. Input is validated character-by-character against the selected source base, so invalid digits produce a clear error rather than a silent wrong answer.

FAQ

Which bases are supported? Any integer base from 2 to 36. Digits above 9 use the letters a–z (case-insensitive).

Is my data sent to a server? No. Every conversion runs entirely in your browser using JavaScript.

Why does it say "invalid digits"? Each base only allows certain characters — for example base 2 accepts only 0 and 1. If your input contains a digit outside that range, the converter reports exactly which characters are invalid.

Does it handle large numbers? Yes, for integers that fit within JavaScript's safe integer range (up to 2⁵³ − 1).