How to convert from hex to decimal. A regular decimal number is the sum of the digits multiplied with power of 10. 137 in base 10 is equal to each digit multiplied with its corresponding power of 10: 137 10 = 1×10 2 +3×10 1 +7×10 0 = 100+30+7. Hex numbers are read the same way, but each digit counts power of 16 instead of power of 10.