Calculate vehicle horsepower, weight, or quarter-mile time by entering any two values, with lb/kg, hp/kW, and seconds/minutes supported.
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Horsepower Quarter Mile Formula
The calculator uses vehicle weight, horsepower, and estimated quarter-mile time. Enter any two values to calculate the missing value.
T = 5.82*(W/HP)^(1/3)
HP = W / (5.82/T)^3
W = (5.82/T)^3 * HP
- T = quarter-mile time in seconds
- W = vehicle weight in pounds
- HP = vehicle horsepower
- 5.82 = quarter-mile estimation constant used by the calculator
The calculator first converts your entries to base units: pounds, horsepower, and seconds. It then uses the formula for the missing field.
- If time is missing, it estimates quarter-mile time from weight and horsepower.
- If horsepower is missing, it estimates horsepower from weight and quarter-mile time.
- If weight is missing, it estimates vehicle weight from horsepower and quarter-mile time.
Quarter-Mile Time Reference
| Quarter-mile time | General performance range | Typical description |
|---|---|---|
| 15 seconds or slower | Normal street vehicle | Average acceleration |
| 13 to 14.9 seconds | Quick street vehicle | Noticeably faster than average |
| 11 to 12.9 seconds | Fast performance vehicle | Strong acceleration |
| 10 seconds or quicker | Very fast drag performance | Often requires serious setup and traction |
Unit Conversions Used
| Input unit | Base unit conversion |
|---|---|
| 1 kilogram | 2.20462 pounds |
| 1 kilowatt | 1.34102 horsepower |
| 1 minute | 60 seconds |
Example
Example 1: Find quarter-mile time
You enter a vehicle weight of 3,200 lb and horsepower of 450 HP.
T = 5.82*(3200/450)^(1/3)
The estimated quarter-mile time is 11.19 seconds.
FAQ
Should you use curb weight or race weight?
Use the weight of the vehicle as it will run the quarter mile. This usually means race weight, including the driver, fuel, and any cargo or equipment in the car.
Is the horsepower result wheel horsepower or engine horsepower?
The formula does not separate wheel horsepower from engine horsepower. Use the same horsepower type when comparing results. If you use wheel horsepower, the result is based on wheel horsepower. If you use engine horsepower, drivetrain loss is not included separately.
Why is the quarter-mile result only an estimate?
The formula is based on weight and horsepower only. Real quarter-mile times also depend on traction, gearing, shift speed, aerodynamics, tire choice, weather, and driver skill.
