Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal instantly, entirely in your browser.
How to Convert Numbers Between Bases for Free
1. Type a number (e.g. 255 or FF) into the Value field.
2. Pick the base your input is written in — Binary, Octal, Decimal, or Hexadecimal.
3. All four bases update instantly as you type, using exact large-integer math.
4. Click the copy icon next to any result to copy that value.
Calculation in Your Browser
Every conversion runs entirely in your browser using plain JavaScript. Nothing you type is ever sent to a server.