Horsepower Calculator
Calculate horsepower from torque and RPM, force and velocity, or watts using three different methods.
Horsepower
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Kilowatts
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Metric HP (PS)
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What is Horsepower Calculator?
The Horsepower Calculator converts mechanical power measurements into horsepower (HP), kilowatts (kW), and metric horsepower (PS). It supports three input methods: torque and RPM, force and velocity, or direct wattage conversion.
How to use
- 1 Select the calculation method: Torque & RPM, Force & Velocity, or Watts.
- 2 Enter the values for your chosen method.
- 3 Click Calculate to get horsepower, kilowatts, and metric horsepower.
- 4 Use the Torque & RPM method for engines — this is the most common method.
- 5 Use the Watts method to convert between electrical and mechanical power ratings.
Formula
Example calculation
An engine producing 300 lb·ft of torque at 5000 RPM: HP = 300 × 5000 / 5252 = 285.6 HP = 213 kW = 289.5 PS.
Frequently asked questions
What is the magic number 5252?
5252 = 33,000 / (2π). It converts the units of torque (lb·ft) and RPM into horsepower. At 5252 RPM, torque and horsepower curves always intersect.
What is metric horsepower (PS)?
PS (Pferdestärke) is the European metric unit. 1 PS = 75 kgf·m/s ≈ 0.9863 HP. It is commonly used for car specifications in Europe and Asia.
Is horsepower the same as kilowatts?
No — 1 HP = 0.7457 kW. Many countries use kW for engine ratings. The calculator shows both.
What is the Force & Velocity method used for?
It is useful for linear systems like electric motors driving conveyor belts or hoists, where you know the pulling force and speed rather than rotational torque.
How is electrical horsepower different?
Electrical horsepower (used for motors) = 746 W exactly, while mechanical horsepower = 745.7 W. The difference is small and the calculator uses 745.7 W.