Quarter-Mile Time Estimator
Use this quarter-mile time estimator to translate vehicle weight, wheel horsepower, and trap speed into an estimated quarter-mile elapsed time (ET) and finish-line speed on a 1,320-foot drag strip.
The underlying equations are empirical fits to real drag racing data, originally popularized by engineer Roger Huntington and refined by decades of racers and tuners.
All calculations assume a standing start over a standard quarter mile with good traction and a mechanically healthy vehicle. Real-world results vary with gearing, aerodynamics, surface prep, weather, and driver skill.
Estimate quarter-mile ET and trap speed from vehicle weight and wheel horsepower using Huntington-style drag racing formulas.
Core inputs
Results
Estimated quarter-mile ET
13.2102
Estimated trap speed
103.1817
Methodology
This estimator uses classic drag racing correlations linking ET and trap speed to the ratio between vehicle weight and wheel horsepower.
For the weight and horsepower method, the calculator uses a Huntington-style fit: ET = 5.825 × (weight / horsepower)^(1/3).
The trap-speed method uses hp ≈ weight × (trap speed / 234)^3 to infer wheel horsepower from terminal speed.
Both methods assume straight-line acceleration, efficient power delivery, and clean shifts without excessive wheelspin.
The formulas are calibrated on typical drag strip conditions and should be considered approximations with expected variance.
Worked examples
Example 1: A 3,600 lb car with 400 wheel horsepower yields an estimated 12.6-second quarter mile.
Example 2: A 2,600 lb lightweight build with 300 wheel horsepower runs a similar ET due to better power-to-weight ratio.
Example 3: A 3,400 lb car trapping 118 mph produces an inferred wheel horsepower used to estimate ET.
Key takeaways
This estimator provides transparent, physics-informed predictions tailored for tuners, engineers, and performance enthusiasts.
Real drag performance depends heavily on traction, weather, and driver technique, so results should be used for planning and comparison rather than certification.
Further resources
Related calculators
External guidance
Expert Q&A
How accurate is this estimator?
Typical predictions are within a few tenths of a second and a few miles per hour, but real-world results depend on traction, weather, and driver technique.
Should I enter engine horsepower or wheel horsepower?
Use wheel horsepower for best accuracy because drivetrain losses can exceed 15 to 25 percent.
Why do the formulas use a one-third power?
The one-third relationship reflects diminishing returns as power increases or weight decreases and matches empirical drag racing data.
Can this be used for eighth-mile tracks?
No. The constants used here are specific to a quarter-mile. Other distances require different regression coefficients.
Is this suitable for street-racing planning?
No. Performance testing should only be conducted at sanctioned facilities that enforce safety regulations.
Sources & citations
- NHRA glossary – definitions of ET and trap speed — https://www.nhra.com/nhra-101/nhra-glossary
- NIST SI units for length and speed — https://www.nist.gov/pml/owm/si-units-length
- MIT OpenCourseWare – classical mechanics, kinematics — https://ocw.mit.edu/courses/8-01sc-classical-mechanics-fall-2016/pages/week-1-kinematics/
- Speedway Motors – Huntington-based drag formulas — https://www.speedwaymotors.com/the-toolbox/drag-racing-calculator-1-4-mile-and-1-8-mile-et-mph-and-horsepower/145871
- NHTSA – safety guidance on speeding — https://www.nhtsa.gov/risky-driving/speeding