Number Base Converter
Convert between binary, octal, decimal, hexadecimal and base 36.
Runs entirely in your browser — nothing is uploaded.
About the Number Base Converter
The Freemium.Tools number base converter converts a number between binary, octal, decimal, hexadecimal and base 36 at once, with support for numbers far larger than a normal calculator allows.
Colour values, permissions, memory addresses and bit flags all live in different bases, and mentally converting hexadecimal to binary is a reliable source of off-by-one bugs.
Type a number, say which base it is in, and every other representation appears instantly along with the number of bits it needs. Big integers are handled exactly, so 64-bit IDs do not lose precision.
How to use it
- 1Choose the input base. Binary, octal, decimal, hexadecimal or base 36.
- 2Type the number. Prefixes like 0x and 0b are accepted and ignored.
- 3Tap any result to copy. Every base is shown at once, plus the bit width.
Frequently asked questions
How do I convert hex to binary?
Select hexadecimal as the input base and type the value; the binary form appears immediately, along with decimal, octal and base 36.
Does it handle very large numbers?
Yes. Conversion uses exact big-integer arithmetic, so 64-bit identifiers and longer values convert without rounding errors.
Can I paste 0x or 0b prefixes?
Yes, common prefixes and separating spaces or underscores are stripped automatically.
What is base 36?
Base 36 uses the digits 0-9 and letters a-z, which makes it a compact way to encode large numbers as short strings in URLs and short links.