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Quarter Mile Calculator
Estimate ET and trap speed from weight and horsepower.
Quarter mile ET
—
Estimated.
| Trap speed | — |
|---|---|
| Weight | — |
| Power | — |
| Power-to-weight | — |
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Enter your figures above to see the step-by-step working.
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How the Quarter Mile Calculator Works
You can estimate a car’s quarter-mile time and trap speed from just its weight and horsepower, using formulas developed by Roger Huntington and refined by others. Elapsed time is about 5.825 times the cube root of weight divided by power; trap speed is 234 times the cube root of power divided by weight. A 3,500-lb, 300-hp car runs roughly a 13.2-second quarter at about 103 mph.
These are estimates — traction, gearing, aerodynamics and driver all shift the real numbers — but they’re a good ballpark from the two figures everyone knows.
ET ≈ 5.825 × (weight ÷ hp)^⅓
Frequently Asked Questions
How do you estimate a quarter-mile time?
From weight and horsepower: ET ≈ 5.825 × (weight/hp)^⅓. A 3,500 lb, 300 hp car is around 13.2 seconds.
What is trap speed?
The speed at the end of the quarter mile. It’s roughly 234 × (hp/weight)^⅓.
How accurate are these formulas?
They’re a solid ballpark, but real times depend on traction, gearing, aero and the driver.
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