Motor Power Calculator
The Motor Power Calculator computes mechanical output power from torque and speed (RPM), input power requirement based on efficiency, and estimated operating current for 3-phase motors.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
Motor Power Calculator
Electric Motor Power & Current Calculator
📐 Formula & Method
Rotational Power
Torque is in N·m and speed is RPM. Output is watts.
Input Power and Current
The current estimate assumes a 415 V three-phase supply and power factor 0.85.
📋 How to Use
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1
Enter torque in N·m.
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2
Enter speed in RPM.
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3
Enter motor efficiency.
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4
Review output kW, HP, estimated input power, and estimated 415 V three-phase current.
🧮 Worked Examples
Validation case
100 N·m at 1450 RPM, 90% efficiency.
Motor Power Calculator — Engineering Reference
Rotational mechanical power is torque multiplied by angular velocity.
The current result is approximate because real current depends on voltage, power factor, motor design, load, starting method, and service factor.
🔬 Methodology & Accuracy
Formula: Converts RPM to angular speed, multiplies by torque for mechanical output power, divides by motor efficiency for input power, and estimates current at 415 V 3-phase with PF 0.85.
Data sources: Standard rotational power equation and three-phase power relationship P = sqrt(3) V I PF.
Last reviewed: June 2026 · General formula used: Rotational Power · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.