Engine Horsepower Calculator
Estimate engine horsepower from quarter-mile time and vehicle weight.
Uses the classic ET-based horsepower formula.
Estimated Horsepower
Horsepower from quarter-mile time uses the widely-known formula:
HP = Weight / (ET / 5.825)³
Where:
- HP = estimated wheel horsepower
- Weight = total vehicle weight including driver (lbs or kg)
- ET = elapsed time for the quarter-mile (seconds)
Imperial formula:
HP = Weight (lbs) / (ET / 5.825)³
Metric formula:
HP = (Weight (kg) × 2.205) / (ET / 5.825)³
Reference quarter-mile times:
| Vehicle Type | Typical ET | Approx. HP |
|---|---|---|
| Economy car | 16–18 sec | 100–150 HP |
| Sports sedan | 13–15 sec | 200–350 HP |
| Muscle car | 11–13 sec | 400–600 HP |
| Supercar | 10–11 sec | 600–800 HP |
Note: This estimates wheel horsepower, not crank horsepower. Drivetrain losses typically account for 10–15% of engine output.