Number Base Converter
Convert numbers between binary, octal, decimal, hexadecimal and any base 2–36.
Runs entirely in your browser — your input never leaves your deviceAbout this tool
This tool converts a number from one base (radix) to another. Enter a value and pick its base — binary (2), octal (8), decimal (10) or hexadecimal (16) — and it instantly shows the equivalent in all the common bases, plus any custom base from 2 to 36.
Big numbers, no rounding
Conversions use JavaScript's BigInt, so very large values convert exactly without the precision loss you'd get from ordinary floating-point math. Negative numbers and the 0x, 0b and 0o prefixes are accepted too.
All conversion happens locally in your browser.
Frequently asked questions
How do I convert binary to decimal?
Set 'From base' to Binary, type your binary digits, and read the Decimal row. For example 11111111 in binary is 255 in decimal.
How do I convert decimal to hexadecimal?
Set 'From base' to Decimal, enter the number, and read the Hexadecimal row. For example 255 becomes ff.
What bases are supported?
Binary, octal, decimal and hexadecimal are always shown, and you can output any base from 2 to 36 using the custom base field. Bases above 10 use letters a–z for the extra digits.
Does it handle very large numbers?
Yes. It uses BigInt, so numbers far larger than a normal 64-bit integer convert exactly, with no rounding.
Is my input sent to a server?
No. The conversion runs entirely in your browser and nothing is uploaded.
Related developer tools
Explore more free tools
Every category runs free in your browser — nothing is uploaded.