Industrial HP Calculators
Tools for pumps, motors, and industrial applications.
In industrial settings, horsepower is calculated from electrical or fluid inputs rather than torque and RPM. These calculators size electric motors from voltage and current, work out pump horsepower from flow and head, and provide a quick motor HP reference chart for single- and three-phase systems.
Industrial vs Automotive Horsepower
The unit is the same — one horsepower is still 745.7 watts — but the inputs differ. An electric motor's horsepower depends on voltage, current (amps), efficiency, and power factor, and changes between single-phase and three-phase supplies. A pump's horsepower depends on the flow rate (GPM) and the head or pressure it must overcome. Getting these right means correctly sized motors, breakers, and wiring.
The Core Formulas
Which Industrial Calculator Do You Need?
| If you want to… | Use this calculator |
|---|---|
| Size an electric motor or its current draw | Electric Motor HP |
| Look up motor HP, amps & kW quickly | Motor HP Chart |
| Size a pump from flow and head | Pump Horsepower |
To convert a motor rating between horsepower and kilowatts, use the HP to kW calculator; to find current from horsepower, see HP to amps.
Every calculator in this hub uses standard published formulas. Results are estimates whose accuracy depends on the values you enter.
Frequently Asked Questions
For a three-phase motor, horsepower = (Volts × Amps × √3 × Power Factor × Efficiency) ÷ 746. For single-phase, remove the √3. This gives shaft horsepower from the electrical input.
Hydraulic (water) horsepower = (Flow in GPM × Head in feet) ÷ 3960. To find the brake horsepower the motor must supply, divide that result by the pump's efficiency.
First calculate the hydraulic horsepower from flow and head, then divide by pump efficiency (typically 0.5–0.85) to get brake horsepower. Choose the next standard motor size above that figure.
It depends on voltage and phase. A 1 HP single-phase 120V motor draws roughly 13–16 amps, while a 1 HP three-phase 230V motor draws about 2.5–3 amps. Use our electric motor HP calculator for your exact case.
The horsepower unit is identical, but three-phase motors use the √3 (1.732) factor in the formula and run more efficiently, drawing less current per horsepower than single-phase motors at the same voltage.