Number Base Converter
5 toolsConvert between binary, octal, decimal, and hex.
Runs in your browser — your files and text stay on your device
A complete converter toolkit — length, weight, temperature, area, volume, speed, data storage, time, and pressure units, plus number bases, CSV/JSON, Roman numerals, and cooking measurements. All in one place, entirely client-side.
Binary
11111111
Octal
377
Decimal
255
Hexadecimal
ff
How to convert a number's base
- 1Type a number into the Value field.
- 2Pick the base it's currently in.
- 3All four bases update instantly.
- 4An error appears if the value has an invalid character for that base.
Frequently asked questions
What bases are supported?
Binary, Octal, Decimal, and Hexadecimal, all shown at once.
Does it handle negative numbers?
No — only non-negative whole numbers.
Is this done on a server?
No — plain JavaScript math running in your browser.