Hex to Decimal Converter

This hex to decimal converter translates hexadecimal numbers into ordinary base-10 decimal, and converts decimal back to hex, as you type. It also shows the binary and octal equivalents, and it uses arbitrary-precision arithmetic so very large values stay exact instead of rounding the way a normal calculator would.

Hexadecimal is base 16: after 9 it continues A, B, C, D, E, F for the values 10 to 15. To convert hex to decimal by hand, multiply each digit by 16 raised to its position from the right and add the results — so 1A4 is (1 × 256) + (10 × 16) + (4 × 1) = 420. Going the other way, repeatedly divide the decimal number by 16 and read the remainders bottom-up.

Hex is everywhere in computing because two hex digits map exactly onto one byte: colour codes like #FF5733, memory addresses, MAC addresses, file signatures, error codes and character encodings all use it. A leading 0x is accepted and ignored, so you can paste values straight out of code or a debugger. Everything is calculated in your browser — nothing is uploaded.