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Engine Horsepower Calculator

Estimate engine horsepower from a car's weight and its quarter-mile trap speed.

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Engine Horsepower Calculator

Calculate engine HP using the Elapsed Time (ET) method.

Uses the HP = Weight × (Speed / 234)³ drag strip formula, also known as the "Hale's Formula". Enter your car's weight and trap speed from a quarter-mile run.

About the Engine Horsepower Calculator

Estimate engine horsepower from a car's weight and its quarter-mile trap speed.

How to use the Engine Horsepower Calculator

  1. Enter the Vehicle Weight (lbs) and Trap Speed (mph).
  2. Press Calculate Engine HP.

Formula and method

HP = weight × (trap speed ÷ 234)³

Worked example

A 3,500 lb car with a trap speed of 110 mph makes about 364 hp.

Tips

  • Use the weight of the car with driver.
  • It is an estimate. A dyno gives the real figure.

Frequently asked questions

What is trap speed?
The speed at the end of a quarter-mile run.