Engine Horsepower Calculator
Estimate horsepower using quarter-mile ET or trap speed methods.
Results
What is Engine Horsepower Estimation?
Engine horsepower can be estimated from quarter-mile performance data without a dynamometer. Two popular methods are the ET (elapsed time) method and the trap speed method, both based on empirical formulas derived from drag racing data.
How to Use This Calculator
- Select the ET Method or Trap Speed Method tab.
- Enter your vehicle weight in pounds.
- Input your quarter-mile time or trap speed.
- Click "Calculate Horsepower" to see the estimated HP.
Frequently Asked Questions
What is the ET method?
The ET method estimates horsepower based on how quickly a vehicle covers the quarter-mile distance. Formula: HP = Weight / (ET / 5.825)^3.
What is the trap speed method?
The trap speed method uses the speed at the end of the quarter-mile. Formula: HP = Weight × (TrapSpeed / 234)^3.
Which method is more accurate?
Trap speed is generally less affected by launch technique, while ET reflects overall power and traction. Use both for a range estimate.
Should I use curb weight or total weight?
Use total vehicle weight including driver, fuel, and any cargo for the most accurate estimate.