Octal to Hex Converter

How to Convert Octal to Hexadecimal

Converting octal to hexadecimal by hand is straightforward once you know the routine. The converter above does it instantly, but working through the steps yourself is the fastest way to understand what is actually happening to the digits.

1. Convert each octal digit into its 3 digit binary form.
2. Join all the bits together into one binary string.
3. Regroup that binary string into blocks of 4, working from the right and padding the left with zeros.
4. Convert each block into a single hexadecimal digit.

Worked example: 764

Result: (764)⁸ = (1F4)¹⁶

The Octal System

Octal is the base 8 numeral system and uses the digits 0 through 7. Its usefulness comes from the fact that one octal digit maps exactly onto three binary digits, so it is a compact way to write binary without doing real arithmetic. Octal was common on early minicomputers with 12, 24, and 36 bit words. Today the place most developers still meet it is Unix file permissions, where a command such as chmod 755 sets read, write, and execute bits three at a time.

Octal uses the digits 0 through 7.

The Hexadecimal System

Hexadecimal is the base 16 system. It uses the digits 0 through 9 and then the letters A through F to stand for the values 10 through 15. Its key property is that one hex digit represents exactly four binary digits, a nibble, so a single byte is always two hex characters. That compactness is why hex shows up everywhere in computing: HTML colour codes such as FFFFFF for white and 000000 for black, memory addresses, MAC addresses, hash digests, and byte level debugging output.

Hexadecimal uses the digits 0 through 9 and A through F.

Octal to Hexadecimal Conversion Examples

Octal to Hexadecimal Conversion Chart

A full reference table for the values 1 to 256. Use it to check a conversion quickly or to look up a common value without typing anything.

Need a different pair of bases? Browse every number converter tool including binary, octal, decimal, and hexadecimal in both directions.