Converters tool

Number Base Converter

Convert binary, octal, decimal, hex and base 2–36.

Free Runs in your browser

Works with whole numbers of any size (BigInt), including negative numbers. Digits above 9 use letters a to z. Prefixes 0x, 0b and 0o are accepted.

About this tool

Number Base Converter turns a whole number written in one base into every other common base at once. It uses BigInt, so even very long numbers convert exactly with no rounding.

How to use Number Base Converter

  1. Type a number.
  2. Choose the base it is written in.
  3. Read binary, octal, decimal, hex and a custom base.

Questions people ask

How do I convert binary to decimal?

Multiply each digit by 2 raised to its position from the right and add them. 1011 = 8 + 0 + 2 + 1 = 11.

Why does hex use letters?

Base 16 needs 16 digits, so a to f stand for 10 to 15. FF in hex is 255 in decimal.

Can it convert fractions?

No. Only whole numbers are supported, because many fractions cannot be written exactly in another base.

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