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Number Base Converter

Convert numbers between binary, octal, decimal and hex.

Last updated: 25 Aug 2026

Quick answer

Enter a number and its base, and this tool converts it to binary, octal, decimal and hexadecimal at once. For example, decimal 255 is 11111111 (binary) and FF (hex). Enter a value and base above.

Convert a number between binary, octal, decimal and hexadecimal in one step. Enter the value and the base it is currently in.

How to convert number bases

  1. 1 Enter the number.
  2. 2 Select the base it is currently in.
  3. 3 See it in binary, octal, decimal and hex.

Frequently asked questions

What is base conversion?
Expressing the same value using a different set of digits — e.g. decimal (base 10) vs binary (base 2).
What is 255 in hex?
FF — and 11111111 in binary.
Are letters allowed?
Yes, for hex (0-9 and A-F).

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