Binary tables offer a free octal subtraction calculator to help you subtract octal numbers. Like octal addition, octal subtraction is at times similar to the process you are familiar with in decimal subtraction. The biggest difference between when octal subtraction and decimal subtraction is where borrowing occurs. In octal subtraction, borrowing happens within the same column (place value) when subtracting a larger digit from a smaller one, adjusting with 8s as needed. This is unlike decimal subtraction, which involves borrowing 10s between columns. If you need to subtract octal numbers try our octal subtraction calculator below to get the subtraction result in both octal and decimal.