Bases and Numerals

Number Base Converter

Convert a value between binary, octal, decimal, hexadecimal and any base from 2 to 36.

Number Base Converter

11111111

255 in base 10 to base 2

Value to convert

Value

From base

To base

Any base from 2 to 36. Binary, octal, decimal and hex are shown below the result.

Convert numbers between bases

This tool converts a value from one number base to another, covering every base from 2 to 36. Enter a value, say which base it is in, and pick the base to convert to. The result appears at once, with binary, octal, decimal and hexadecimal all shown for reference.

How base conversion works

A number base is just how many digits are used before a column rolls over. Decimal uses ten, binary two, hexadecimal sixteen. The converter reads your value in its own base, works out the plain quantity, and writes it out in the target base, using letters for digit values above nine.

Reading the reference line

Under the result the tool lists the same value in binary, octal, decimal and hex together, which is handy when you are working across programming, colour codes or low level data and need to see all four at a glance.

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Frequently asked questions

Which bases are supported

Any base from 2 to 36, since digits run out at the 10 numerals plus the 26 letters. Binary, octal, decimal and hexadecimal are the common ones and are shown together.

How do I read hexadecimal

Hex uses the digits 0 to 9 then the letters A to F for 10 to 15, so FF is 255. The converter shows letters in upper case.

Can I convert letters and digits

Yes. For bases above 10 you can enter digits and letters, for example 1A in base 16, and convert to any other base.

Does it handle negative numbers

Yes. A leading minus sign is kept, so minus values convert and display with the sign.

Is it free

Yes, free and with no sign up. Everything runs in your browser and nothing you enter leaves your device.

Related generators

For random values in a base see the binary, hex or octal generators.