Estimate horsepower from vehicle weight and quarter-mile trap speed (a common drag-racing rule of thumb).
Uses the common quarter-mile trap-speed formula — a rough estimate, not a dyno-accurate reading.
It's a rough rule-of-thumb used in drag racing, not a dyno-accurate measurement. Real-world factors like aerodynamic drag, tire grip, drivetrain losses and driver skill all affect trap speed independently of pure engine power, so treat the result as a ballpark figure.
Use the vehicle's total weight including the driver, measured in pounds — this matches the formula's "Weight (lb)" input, since a heavier car needs more power to reach the same trap speed.
Trap speed is the vehicle's speed measured at the very end of a quarter-mile drag strip run (the "speed trap"), typically in mph — it's one of the two standard numbers (alongside elapsed time) reported from a drag strip pass.