How can I convert a number from base 8 to base 10?

Question

I know 75(base8) = 61(base10), but I can't easily find the formula for this. How does one convert from base 8 to base 10?

Answer 1

To convert any base to base 10 just do the following:

For every digit in the different base multiply that by the base and digit. For example:

75 (base 8) = 7*8^1 + 5*8^0 = 61 

Works for any base ... binary, hex, you name it just do that and it will convert to base 10.