How it works
Estimate your vehicle’s 1/4 mile elapsed time (ET) and terminal trap speed based on power-to-weight ratio.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
2-
?weight=Total Weight (lbs)Number · Optional · Default: 3,500
-
?power=Flywheel Power (HP)Number · Optional · Default: 400
Outputs
1-
resultResultText · Primary output
result contains the calculator’s complete rendered result area, including its visible result cards, tables, charts, and messages.
Estimate your vehicle’s drag racing performance based on weight and power
Description
The Quarter Mile Calculator is an essential tool for automotive enthusiasts, drag racers, and tuners. It uses physics-based formulas (specifically the Hale formula) to estimate two key performance metrics: Elapsed Time (ET) and Trap Speed. By entering the vehicle’s total Weight (including the driver) and its engine Horsepower, you can see what kind of performance to expect at a standard 402-meter (1/4 mile) drag strip.
Inputs
- Weight (lbs): The curb weight of the vehicle plus the weight of the driver and fuel.
- Horsepower (HP): The net power output of the engine (preferably at the wheels for better accuracy).
Outputs
- Estimated ET: The predicted time in seconds to reach the finish line.
- Trap Speed: The predicted speed in MPH as the vehicle crosses the finish line.
Chart
- N/A: This tool provides precision numeric automotive results.
“Good to Know”
- The Physics: ET is primarily influenced by the weight-to-power ratio. However, real-world times also depend heavily on traction, gear ratios, and weather conditions (air density).
- Wheel vs. Crank HP: Most manufacturers cite “crank” horsepower. Wheel horsepower (WHP) is typically 15-20% lower due to drivetrain loss. Using WHP will give you a more “realistic” time, while Crank HP gives you the “theoretical maximum.”
- Traction: This calculator assumes a “perfect” launch with ideal traction. Front-wheel drive cars or cars with street tires may struggle to hit these theoretical times.
Examples
Example 1: Modern Muscle Car
- Input: 3800 lbs, 485 HP
- Output: 11.58 s @ 117.84 mph
Example 2: Lightweight Sports Car
- Input: 2800 lbs, 300 HP
- Output: 12.29 s @ 109.13 mph
Example 3: Modified Supercar
- Input: 3500 lbs, 800 HP
- Output: 9.53 s @ 142.15 mph