Motor FLA Calculator

Motors dominate industrial current draw, and their amps do not follow the simple watts / volts line — efficiency and power factor add real current on top. Getting FLA right is the difference between a motor that runs cool and one that trips all night.

Motor FLA Calculator computes full-load amps from power (kW or HP), voltage, phase count, efficiency and power factor, then adds the inrush view and a suggested breaker and cable size.

Everything runs in the browser; nothing is uploaded.

• kW or HP input: Convert between units at the press of a button.
• Single and three-phase: The right formula for each system.
• Efficiency and pf: Realistic defaults with full control.
• Inrush estimate: Locked-rotor current for startup planning.
• Protection guide: Suggested overload and breaker context.
• Export: Copy or download the calculation as text, CSV or JSON.
• Learning guide: Why a motor never draws its kW / volts.

1. Enter the motor power in kW (or HP).
2. Select the phase count and enter the supply voltage.
3. Set efficiency and power factor from the nameplate.
4. Read the FLA and the inrush estimate.
5. Check the suggested breaker context for the frame.
6. Export the calc for your schedule.

Example 1 — Three-phase. 11 kW, 400 V, eff 0.9, pf 0.85: about 20.8 A FLA.

Example 2 — Single-phase. 2.2 kW, 230 V, eff 0.85, pf 0.9: about 12.5 A.

Example 3 — Inrush. A 15 kW motor at 6x inrush pulls about 150 A for a moment on startup.

Example 4 — HP. 10 hp (7.46 kW) three-phase 400 V at eff 0.87, pf 0.8: about 15.5 A.

• Nameplate-grade FLA: Efficiency and pf built into the formula.
• Startup awareness: Inrush estimate for contactor and breaker work.
• Both unit systems: kW and HP supported cleanly.
• Protection context: Overload and breaker sizing guidance.
• Free and private: No uploads, no accounts, no logging.