Horsepower Calculator - calculatorsee.com


Horsepower Calculator

Calculate engine horsepower from torque (lb-ft) and RPM, or estimate vehicle horsepower from quarter-mile elapsed time and trap speed.

Calculator Inputs

lb-ft
Measured engine torque.
RPM
Rotational speed.

Calculated Results

Calculated Horsepower
366.52 HP (273.31 kW)
Kilowatts (kW) 273.31 kW
Metric PS (Pferdestärke) 371.60 PS
Engine Flywheel Torque 350.00 lb-ft (474.5 N·m)
Values calculate live as you adjust inputs.

About Horsepower Calculator

Computes mechanical horsepower developed by an internal combustion engine or electric motor: HP = (Torque × RPM) / 5252.

What is Horsepower Calculator?

Computes mechanical horsepower developed by an internal combustion engine or electric motor: HP = (Torque × RPM) / 5252.

How to Use This Calculator

  1. Enter engine torque in lb-ft.
  2. Enter engine RPM.
  3. Review horsepower, kilowatts, and metric PS.

The Mathematical Formula & Variables

Horsepower = (Torque in lb-ft * RPM) / 5252; kW = HP * 0.7457

Step-by-Step Worked Example

Scenario: 350 lb-ft torque at 5,500 RPM.

  1. HP = (350 * 5,500) / 5,252 = 1,925,000 / 5,252 = 366.52 HP.
  2. In kW: 366.52 * 0.7457 = 273.31 kW.

Result: 366.52 HP

Frequently Asked Questions

Why do horsepower and torque curves always cross at 5,252 RPM?

Because in the standard formula HP = (Torque * RPM) / 5252, when RPM equals 5,252, the RPM and 5,252 terms cancel out, making HP exactly equal to Torque.