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Horsepower from MPH Calculator
Estimate horsepower from weight and trap speed
Horsepower from trap speed estimates flywheel horsepower from race weight and finish-line speed — the method least affected by traction.
Formula: HP = Weight × (MPH ÷ 234)³
What this number means
This estimates horsepower from race weight and quarter-mile trap speed. Because trap MPH is less affected by traction than ET, it is the cleaner measure of power actually reaching the track.
What to change next
Compare it with your ET-based estimate: a big gap means the chassis and launch are wasting power you already have. If MPH power matches your build expectations, tune the launch, not the engine.
Worked example
A 3,200 lb car trapping 120 MPH in the quarter gives ≈ 432 hp.