Octal to Decimal Converter

Enter octal number:
Decimal result:
Hex result:

This is a number conversion calculator that is used to convert the values in octal (base 8) to decimals (base 10). It uses three simple controls that perform different functions of the calculator. The first procedure of using this converter is by filling in the octal number in the blank text field provided. Afterward, click the ‘Convert' button to initiate the conversion. The results will be displayed immediately at the bottom platform of the calculator below the controls. If you want to carry out new calculations you will use the ‘Reset' button to readjust the calculator. The ‘Swap' button is used to alternate the alignment of the calculator allowing you to convert from the decimals to octal.

For example;

Convert 25 (8) to decimals.


First, enter the value 25 in the blank text field and then click the ‘Convert' button. The results will be displayed as;

Decimal result: 21

Hex result: 15

This calculator uses a simple formula in executing the conversions. You can only perform a single conversion at a time with the octal to decimal converter. If you have the values in decimals, you need to use the decimal to octal converter. This calculator gives accurate results depending on the values entered in the text field.

Formula of converting octal to decimal

A regular decimal number is determined by the multiplying the sum of the digits with 10n.


126 in base 10 is calculated by multiplying each digit with its corresponding 10n.

12610 = 1 x 102 + 2 x 101 + 6 x 100 = 100 +20 + 6

Although a similar way is used to read the octal numbers, every digit counts 8n instead of 10n. Each digit of the hex number is then multiplied by its corresponding 8n. You get accurate results in lesser time.