How to Convert Amperage to Horsepower

If you want to determine how much mechanical work an electrical motor can do in a given time, or how much power it has, you need to know the voltage flowing into it and the current in amperage. Determining these measurements will allow you to calculate how much electrical horsepower the motor has. Converting from amperage to horsepower assumes no energy loss due to electrical resistance or friction.

Things You'll Need

• Calculator

Instructions

1. Look on your motor's nameplate to find the full load current in amps; i.e., the amount of current the motor draws when running at top speed. One example is a 16-amp full load.

2. Determine the voltage going to your motor. If you have it plugged into a standard household outlet, your motor will receive 120 AC voltage.

3. Multiply the current by the applied voltage to get the wattage. A 16-amp full load current will use 1,920 watts of power on a 120-volt line.

4. Divide the result by 746. A motor that uses 1,920 watts at a 16-amp full load current has an output of 2.6 horsepower.

References

• Auburn University: Energy Conversion