Number Base Converter

Convert whole numbers between binary, octal, decimal, hexadecimal, and any base from 2 to 36. Uses exact big-integer math, so long values keep every digit. Calculates in your browser.

Binary (2)-
Octal (8)-
Decimal (10)-
Hexadecimal (16)-
Custom base -

How it works

The value is read as a whole number in its source base, then re-written in each target base. Digits above 9 use letters: a=10 through z=35, so decimal 255 is ff in hex.

Conversions use exact big-integer math, so even very long binary strings keep every digit. Letters are case-insensitive on input.

What this does

A number base converter changes a whole number between binary, octal, decimal, hexadecimal, and any base from 2 to 36. It uses exact big-integer math, so even very long values keep every digit.

How to use it

  1. Enter your value and its current base.
  2. Read the binary, octal, decimal, and hex results.
  3. Set a custom base from 2 to 36 if needed.

Example

Decimal 255 is 11111111 in binary and ff in hexadecimal; decimal 8 is 10 in octal.

Last updated .

Frequently asked questions

Which bases are supported?

Any base from 2 to 36. Binary, octal, decimal, and hexadecimal are shown by default, and you can convert to a custom base as well.

How are digits above 9 written?

With letters: a is 10, b is 11, and so on up to z which is 35. So decimal 255 is ff in hexadecimal. Input letters are case-insensitive.

Will big numbers lose precision?

No. Conversions use exact big-integer arithmetic, so even very long binary strings convert without rounding.

Is my data stored?

No. Everything is calculated locally in your browser, nothing is uploaded or saved.