Estimate motor starter size from motor horsepower, full-load amps, voltage, phase type, service factor, overload class, starter type, and starting method. This calculator helps estimate contactor size, overload range, starter amp rating, starting amps, and starter planning values.
Motor current:
The calculator estimates full-load amps from horsepower, kW, watts, or entered nameplate amps.
Starter sizing:
It applies service factor, overload setting, and starter duty margin to estimate a planning starter amp size.
Starting load:
Startup multiplier and starting method are used to estimate starting amps and starting kVA.
A motor starter size calculator helps estimate starter amp rating, overload setting, contactor size, and starting current before selecting equipment.
It can help with pumps, fans, compressors, conveyors, HVAC motors, shop equipment, industrial loads, manual starters, magnetic starters, soft starters, and VFD planning.
Your result shows estimated starter amp size, full-load amps, overload setting, overload range, contactor planning size, starting amps, starting kVA, motor horsepower, kW, voltage, phase type, and starter duty notes.
Motor starters are commonly selected using motor horsepower, voltage, phase, full-load amps, starter type, duty rating, and manufacturer starter tables.
No. The starter includes switching equipment such as a contactor, while overload protection is adjusted or selected to protect the motor from sustained overload.
For real installations, use motor nameplate full-load amps and the starter manufacturer’s selection charts.
No. This calculator gives a planning estimate. Final starter, overload, fuse, breaker, conductor, disconnect, and controller selection must follow code, nameplate data, and manufacturer instructions.