Quarter Mile Calculator

You can use this quarter mile calculator to determine the terminal speed (trap speed) and quarter-mile elapsed time (ET) of a vehicle based on its weight and power.

How to use the quarter mile calculator:

  • 1. Select which unit system of measurement you need from the drop-down menu
  • 2. Select which equation you would like to use to calculate the terminal speed at the end of the quarter-mile and the quarter-mile ET
  • 3. Enter the total weight of both the vehicle and the driver
  • 4. Input the power of the vehicle's engine
  • 5. Click on the "Calculate" button to generate the calculation.
1/4 Mile ET & Trap Speed Calculator




Quarter-Mile Performance

When estimating quarter-mile performance, some key variables should be taken into consideration. These include driver skill, fuel type, temperature, gearing, humidity, and drivetrain power loss.

To achieve an optimal quarter-mile time, a launch is imperative. If the launch is executed at a high rpm, the vehicle will suffer a loss of traction. If the launch is performed at a low rpm, this may make the vehicle sluggish and fail to optimize on the potential of the vehicle's torque and horsepower.

Front-wheel drive vehicles are commonly lighter than the rear-wheel counterparts. However, they typically experience a traction loss due to the weight shift. This is particularly the case with high-powered vehicles. As such, while tire grip is important within all vehicles, it is particularly significant for front-wheel drivetrains.

ET & MPH Equations

The quarter mile calculator employs three distinct empirical equations to determine the ?-mile ET and trap speed estimates. These are as follows:

Roger Huntington's Equations:

ET Equation: ET = 6.290 × (WT / HP) 1/3
MPH Equation: MPH = 224 × (HP / WT) 1/3

Geoffrey Fox's Equations:

ET Equation: ET = 6.269 × (WT / HP) 1/3
MPH Equation: MPH = 230 × (HP / WT) 1/3

Patrick Hale's Equations:

ET Equation: ET = 5.825 × (WT / HP) 1/3
MPH Equation: MPH = 234 × (HP / WT) 1/3


ET is the ?-mile elapsed time (seconds),

MPH is the ?-mile trap speed of vehicle (mph),

WT is the total weight of the vehicle and driver (lbs),

HP is the peak engine horsepower (hp).

*It is important to note that these equations can only produce "approximations" of an "estimated" value. The outputs are not exact.

You may also be interested in our Power to Weight Ratio Calculator

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