Drag racing turns horsepower, weight, and traction into elapsed time (ET) and trap speed. These calculators let you predict a quarter-mile run, estimate horsepower from a timeslip, work out your power-to-weight ratio, and project a 0–60 time — all from a few basic numbers.

How Drag Racing Math Works

Two numbers define a drag run: elapsed time (ET), how long it takes to cover the distance, and trap speed (MPH), how fast you are going at the line. Both are governed by the relationship between power and weight. The widely used empirical formulas (Patrick Hale's racing equations) connect these so accurately that you can estimate horsepower from a timeslip alone, or predict ET before you ever make a pass.

The Core Formulas

Trap-speed horsepower
HP = Weight × (MPH ÷ 234)³
Weight in pounds (car + driver), MPH at the quarter-mile trap.

From the same physics, the HP from ET calculator uses elapsed time instead of speed, while the quarter mile calculator predicts ET and MPH from your horsepower and weight. Because acceleration depends on power per pound, the power-to-weight ratio is the single best predictor of how quick a car will be.

Which Racing Calculator Should You Use?

If you want to…Use this calculator
Predict quarter-mile ET & trap speedQuarter Mile Calculator
Estimate HP from a timeslip ETHorsepower from ET
Compare performance per poundPower-to-Weight Ratio
Estimate 0–60 mph time0-60 mph Calculator

Every calculator in this hub uses standard published formulas. Results are estimates whose accuracy depends on the values you enter.

Frequently Asked Questions

They provide theoretical best-case estimates assuming perfect traction and optimal gearing.

Estimates are typically within 5–10% for a well-prepared car. Traction, gearing, weather, and launch technique cause most of the real-world variation.

ET is the time to cover the distance; trap speed is the MPH at the finish. Trap speed correlates more closely with horsepower, while ET also depends on the launch.

Strongly, yes. It's the best single predictor, though traction sets a ceiling on how much power can actually reach the track.

Yes. Both trap speed and elapsed time can estimate horsepower using Hale's formulas — use the HP from ET or trap-speed HP calculators.