⚡ Horsepower Calculator
Calculate engine power from torque and RPM
Horsepower = 0 HP
(Torque × RPM) ÷ 5252
How Is Horsepower Calculated?
Horsepower (HP) is a measure of an engine's power output. When you know the torque (in pound-feet) and the engine speed (RPM), you can use the standard formula:
Horsepower = (Torque × RPM) ÷ 5252
The number 5252 is a constant that comes from the mathematical relationship between rotational motion and linear power (33,000 foot-pounds per minute divided by 2π). That's why the torque and horsepower curves of an engine always cross at 5,252 RPM.
Why Use This Calculator?
- Quick and accurate: No manual math needed.
- Universal formula: Works for any internal combustion engine or electric motor rated in lb‑ft.
- Clear results: See your horsepower instantly.
Example Calculations
If an engine produces 300 lb‑ft of torque at 4,000 RPM:
Horsepower = (300 × 4000) ÷ 5252 ≈ 228 HP
At 6,000 RPM with the same torque: (300 × 6000) ÷ 5252 ≈ 343 HP.
Frequently Asked Questions
Can I use Nm (Newton-meters) instead?
This calculator is designed for torque in pound-feet. If you have Nm, convert it first (1 lb‑ft ≈ 1.3558 Nm) or use a metric formula.
Does this work for electric motors?
Yes, the formula is identical as long as torque is in lb‑ft and rotational speed in RPM.
