Which number bases are supported?

You can input a value in binary (base 2), octal (base 8), decimal (base 10), or hexadecimal (base 16), and instantly see it converted to all four bases.

Why does it say my value is invalid?

The value must contain only digits allowed in the selected base. For example, the digit 9 or letters are not valid in binary, so switch to the correct input base or fix the value.

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Number Base Converter

Convert numbers between binary, octal, decimal and hex.

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How to use the Number Base Converter

1Type a number into the Value field.
2Choose the input base (2, 8, 10, or 16).
3Copy the binary, octal, decimal, or hex result.

About the Number Base Converter

Free online number base converter to instantly convert between binary, octal, decimal and hexadecimal. Enter any value, pick its base, and copy results.

Part of our Developer Tools collection. Browse all tools.

Frequently asked questions

Which number bases are supported?: You can input a value in binary (base 2), octal (base 8), decimal (base 10), or hexadecimal (base 16), and instantly see it converted to all four bases.
Why does it say my value is invalid?: The value must contain only digits allowed in the selected base. For example, the digit 9 or letters are not valid in binary, so switch to the correct input base or fix the value.