Motor Power and Torque Calculator

Calculate mechanical power, torque, and rotational speed for electric motors using standard engineering formulas.

Calculate:

Torque (T):

Rotational Speed (n):

Power (P):

Motor Efficiency (η): (optional, 1–100%)

Mechanical Power:
P = T × ω
where ω = 2πn/60 (rad/s) when n is in RPM

Torque:
T = P / ω

Rotational Speed:
ω = P / T → n (RPM) = ω × 60 / (2π)

Efficiency:
P_mech = P_elec × η
η = mechanical output power / electrical input power

Unit Conversions:
1 ft·lb = 1.35582 N·m | 1 in·lb = 0.112985 N·m
1 hp = 745.69987 W | 1 kW = 1000 W

Calculations assume steady-state operation (constant speed and torque).
Efficiency (η) accounts for all losses (friction, heat, electrical); defaults to 100% (ideal motor) if not specified.
Angular velocity ω = 2πn/60, where n is rotational speed in RPM.
Mechanical power formula: P = Tω — derived from rotational mechanics (SI units: Watts, N·m, rad/s).
Does not account for transient conditions, starting torque, or load variations.
References: ISO 80000-4 (Mechanics), NEMA MG 1 Motor Standards, IEC 60034 Rotating Electrical Machines.

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