Number Converters · Browser · Free

Octal to Hex Converter

Type an octal number and get the same value written in hexadecimal, with its binary and decimal forms shown alongside. Numbers separated by spaces are converted one at a time.

Octal to hexadecimal conversion

This tool takes a number written in octal and writes the same value in hexadecimal. It also shows the binary and the decimal form of that value, so you can read the two base systems against each other.

The form is a single text field. A sign in front of the number and a fractional point inside it are both accepted, and when you separate several numbers with spaces each one is converted on its own. Letters in the answer print in uppercase.

Nothing is worked out until you press Convert. The answer then appears in a card below the button, where Copy writes the result together with its unit to the clipboard and Clear puts the field back to empty.

Octal to hexadecimal formula

Both bases are positional, which means a digit is worth whatever its place makes it worth. Octal is base 8, so each place to the left is worth eight times the one before it, and it writes with the digits 0 to 7. Hexadecimal is base 16, so its places step up by sixteen, and after 0 to 9 it uses the letters A to F for the higher digits.

Take the octal number 20. Its left digit counts groups of eight and its right digit counts single units, so it says two eights and nothing over. Read in hexadecimal, that same amount is one group of sixteen with nothing left over, which is why the table prints it as 10.

Bigger amounts work the same way, and you can read them straight off the table instead of working them out: octal 37 is written 1F, octal 144 is written 64, octal 377 is written FF, octal 400 is written 100, and octal 2000 is written 400.