Base-8 numbering. Only digits 0–7 are used. E.g. octal 10 = decimal 8.

How do I add octal numbers?

Enter two octal values (0–7 only). The tool adds or subtracts and shows the result in octal and decimal.

Can I convert decimal to octal?

Yes. Use the converter mode to switch between octal and decimal.

Add or subtract octal numbers, or convert between octal and decimal.

Octal A

Octal B

What is octal?: Base-8 numbering. Only digits 0–7 are used. E.g. octal 10 = decimal 8.
How do I add octal numbers?: Enter two octal values (0–7 only). The tool adds or subtracts and shows the result in octal and decimal.
Can I convert decimal to octal?: Yes. Use the converter mode to switch between octal and decimal.

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