Motor HP Calculator | Calculate Horsepower from Voltage & Current

Motor HP Calculator

Estimate motor horsepower from electrical measurements using IEEE/IEC-style power relations.

Standards-aligned relations

P_in = V·I·PF (1Φ),   P_in = √3·V·I·PF (3Φ)

Inputs

Enter measured line values. Efficiency is motor efficiency (output ÷ input).

Phase

Use line-to-line voltage for 3Φ line voltage (typical measurement).

Line Voltage (V)

V

Line Current (A)

A

Power Factor (cos φ)

pu

Efficiency (η)

%

Please correct the following:

Results

Rounded to 2 decimals

Input Power

—

kW

Real electrical power into the motor (P_in).

Output Power

—

kW

Mechanical shaft output power (P_out = P_in·η).

Motor Power

—

HP

HP = kW ÷ 0.746

Apparent Power

—

kVA

S = V·I (1Φ) or √3·V·I (3Φ)

Reactive Power

—

kVAR

Q = √(S² − P_in²) (assuming sinusoidal steady-state)

Disclaimer: For estimation purposes only. Always verify with motor nameplate data.

Notes: The calculator uses line quantities. Efficiency η is entered in percent and applied to convert electrical input power to mechanical output. Reactive power is derived from the power triangle using the entered power factor.