Estimate engine horsepower using trap speed or elapsed time methods
Our Engine Horsepower Calculator estimates crankshaft horsepower using two common quarter-mile drag strip methods. The trap speed method uses vehicle weight and trap speed, while the ET (elapsed time) method uses weight and quarter-mile time. Both estimates are displayed side by side for comparison.
These formulas provide reasonable estimates for typical street cars. Actual engine output may vary based on drivetrain losses, traction, weather conditions, and vehicle aerodynamics.
The trap speed method is generally considered more accurate because trap speed is less affected by traction and driver skill than ET. The ET method can be skewed by excellent or poor launches. For the most reliable estimate, average both methods together.
No, these formulas estimate crankshaft (flywheel) horsepower. Actual wheel horsepower is typically 10-20% lower depending on the drivetrain type (manual ~10-15% loss, automatic ~15-20% loss, AWD ~20-25% loss).