Horsepower Calculator
Estimate engine horsepower from torque and RPM, with conversions to kW and PS.
Results
Horsepower (HP)
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Kilowatts (kW)
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Metric Horsepower (PS)
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What is Horsepower?
Horsepower (HP) is a unit of measurement for power, originally defined by James Watt to compare the output of steam engines with the power of draft horses. In automotive and mechanical engineering, it quantifies the rate at which work is done by an engine.
How to Use This Calculator
- Enter the engine torque value in lb-ft or Nm.
- Input the engine RPM (revolutions per minute).
- Click "Calculate Horsepower" to see HP, kW, and PS values.
Frequently Asked Questions
What is the formula for horsepower?
HP = (Torque in lb-ft × RPM) / 5252. If torque is in Nm, first convert to lb-ft by dividing by 1.3558.
What is the difference between HP and kW?
Kilowatt (kW) is the SI unit of power. 1 HP is approximately 0.7457 kW.
What is metric horsepower (PS)?
PS (Pferdestärke) is a metric unit commonly used in Europe. 1 HP equals approximately 1.0139 PS.
Can I use this for electric motors?
Yes, the formula applies to any rotating machinery where torque and RPM are known.