Amps measure electrical current. Horsepower is the amount of energy a motor creates when in use. Given horsepower and volts, it is possible to calculate amps. The calculation of amps uses Ohm's Law, which is amps times volts equals watts.

Multiply the horsepower by 746 watts. For example, an engine at two horsepower with 230 volts would be calculated as two horsepower times 746 watts, which equals 1492.

Divide the number calculated in Step 1 by the amount of volts to calculate watts. In the example, 1492 would be divided by 230, which equals about 6.49 amps.

Check the calculations. It is always helpful to look over any mathematical calculations in order to reduce the risk of mathematical errors.