Three Phase Motor Calculator

Calculate three-phase motor amps, horsepower, kilowatts, kVA, input power, output power, efficiency, starting current, and energy cost. This calculator is useful for three-phase motor load planning, starter planning, breaker planning, and electrical service estimates.

Calculate Three Phase Motor Values

Three-phase motor amps = watts ÷ (√3 × volts × efficiency × power factor).
Your result will appear here.

How the three phase motor calculator works

Motor power:
The calculator converts horsepower to output watts or uses entered kW and amps.

Three-phase current:
It uses √3, line-to-line voltage, efficiency, and power factor to estimate motor current.

Planning values:
It estimates running amps, service-factor amps, starting amps, kVA, monthly kWh, and energy cost.

Why use a three phase motor calculator?

A three phase motor calculator helps estimate electrical values for industrial motors, pumps, fans, compressors, conveyors, shop equipment, HVAC motors, and production equipment.

It can help with motor load planning, starter sizing, breaker planning, fuse planning, panel capacity checks, generator sizing, and energy cost estimates.

What your result means

Your result shows three-phase motor amps, horsepower, output watts, output kW, input watts, input kW, kVA, starting amps, service-factor amps, energy use, monthly cost, and comparison motor estimates.

Three phase motor calculator formulas

Frequently asked questions

How do I calculate three-phase motor amps?

Convert horsepower to watts, then divide by √3, line-to-line voltage, efficiency, and power factor.

Why does three-phase use √3?

Balanced three-phase power uses the square root of 3 when calculating power from line-to-line voltage and line current.

What voltage should I use?

Use the motor’s line-to-line voltage, such as 208V, 230V, 460V, 480V, 575V, or the value shown on the motor nameplate.

Can this calculator size the final breaker and wire?

No. This calculator gives planning estimates. Final motor circuits must follow motor nameplate data, electrical code, manufacturer instructions, and local inspection requirements.