Number Base Converter
Binary, octal, decimal and hex.
- 100% free
- No sign-up
- Runs in your browser
Switch bases without the maths
Enter a number in binary, octal, decimal or hexadecimal and see it in every other base at once. Large values are handled exactly, with no rounding.
Prefixes like 0x and 0b, spaces and underscores are ignored, so you can paste values straight from code.
- 1
Pick the input base
2, 8, 10 or 16.
- 2
Type the number
Prefixes are fine.
- 3
Copy any result
Click to copy.
Frequently asked questions
Does it handle negative numbers or fractions?
It's designed for non-negative whole numbers, which covers most programming use.
Why is hex used for colours?
Two hex digits describe exactly one byte (0–255), so #RRGGBB maps neatly to red, green and blue.
Is my data uploaded anywhere?
No. Everything runs in your browser with JavaScript — nothing you type or open is sent to our servers.