Number Converters · Browser · Free

Hex to Octal Converter

Type a hexadecimal value into the single field and press Convert to get the octal equivalent. The binary and decimal forms appear beside it, and any letters print uppercase.

About this converter

This tool takes a hexadecimal number and writes the same amount in octal. Hexadecimal is base 16 and octal is base 8, so the two notations use different digits for one and the same amount. The result card lists the octal form together with the binary and decimal forms of what you entered.

Everything goes through one text field. A leading sign is accepted and a fractional point is accepted, and several numbers separated by spaces are converted one by one. Letters in the answer always print in uppercase.

How hexadecimal and octal relate

Both notations are positional, which means a digit says something different depending on where it sits. In a hexadecimal number each place is worth sixteen times the place to its right, and a hexadecimal digit can be one of sixteen symbols: 0 to 9 and then A to F. In an octal number each place is worth eight times the place to its right, and a digit can only be one of eight, 0 to 7.

Because the places grow at different rates, one amount can need fewer hexadecimal digits than octal digits. The table shows this plainly: A prints as 12, 1F prints as 37, FF prints as 377, and 400 prints as 2000.

Hex to Octal formula

Read the hexadecimal digits as places that step by sixteens, keep the amount they stand for, and write that same amount with places that step by eights. Nothing about the number changes, only the symbols and how many of them you need.

Take the row 1F to 37 from the table. On the left, the places are sixteens: the leading 1 covers one full group of sixteen and the F covers what is left over. On the right, the same amount is grouped by eights instead: 3 full groups of eight and 7 single units beside them.