Motor Starter Size Calculator — Free Online Calculator

Size motor starters, contactors, and overload relays based on motor HP, voltage, and full load amps.

How to Use This Calculator

Enter motor HP, voltage, and phase.

The Formula Explained

FLA estimated from HP rating with typical efficiency and power factor. Overload = FLA × 115% per NEC 430.32. NEMA starter size based on HP and voltage ranges.

Frequently Asked Questions