Converts numbers between binary, octal, decimal and hex.
The Number Base Converter turns a value between binary, octal, decimal, and hexadecimal, showing all four representations at once. Paste a number and it either auto-detects the input base from prefixes like 0x, 0b, or 0o, or you can pick the source base manually. It uses arbitrary-precision integers, so very large values convert without rounding or overflow.
No. The conversion runs entirely in your browser using JavaScript, and nothing you type is uploaded or stored on any server.
It reads and outputs binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Every conversion shows all four results together.
With the From option set to Auto-detect, an input starting with 0x is read as hex, 0b as binary, and 0o as octal; anything else is treated as decimal. You can also set the source base explicitly instead of relying on prefixes.
Yes. It uses arbitrary-precision (BigInt) arithmetic, so large values convert exactly without floating-point rounding or overflow.
If a character is not valid for the selected base, such as a 9 in a binary input, it reports an error naming the invalid digit and the base instead of producing a result.