1/4 mile ET & trap speed estimator

Quarter Mile Calculator

Type in your car’s race weight and horsepower and get an estimated quarter-mile time and trap speed, along with the matching 1/8-mile numbers. It is free, runs in your browser and needs no account.

Result

Quarter-mile ET

sec

Trap speed

mph

QuicknessQuick street car

1/8-mile ET: 7.69 sec
1/8-mile speed: 90.8 mph
Trap speed: 182.8 km/h
Weight per hp: 8.75 lb/hp
Conservative ET (Huntington): 12.96 sec
Conservative trap (Huntington): 108.7 mph

Staged and ready

How this quarter mile calculator works

A quarter-mile run is mostly a power-to-weight contest, so the calculator needs just two numbers: how much the car weighs ready to race (driver included) and how much horsepower the engine makes at the crank. From those it computes elapsed time (ET) and the speed you cross the finish line at, called trap speed or MPH.

For the default 3,500 lb and 400 hp, the formula gives 12.00 seconds at 113.6 mph. Below it you also get the 1/8-mile equivalent, the same run in km/h, and a second, more conservative range for cars that won’t launch perfectly.

The estimate uses the widely published Patrick Hale equations: ET = 5.825 × (weight ÷ hp)^1/3 and MPH = 234 × (hp ÷ weight)^1/3, with weight in pounds and hp measured at the crank. They are documented, along with the more conservative Huntington (6.290 / 224) and Fox constants, in Stealth316’s horsepower / ET / MPH calculator notes. See the full formulas and sources page.

Quarter-mile time by horsepower and weight

This quick-reference grid uses the same formula as the calculator. Find your weight on the left, your horsepower across the top, and read the estimated ET in seconds.

Weight ↓ / Power →	200 hp	300 hp	400 hp	500 hp	600 hp	800 hp
2,800 lb	14.04	12.26	11.14	10.34	9.73	8.84
3,200 lb	14.68	12.82	11.65	10.81	10.18	9.25
3,600 lb	15.27	13.34	12.12	11.25	10.58	9.62
4,000 lb	15.81	13.81	12.55	11.65	10.96	9.96
4,400 lb	16.32	14.26	12.95	12.03	11.32	10.28

Estimates assume full traction, a good launch and near sea-level air. Treat them as a target, not a guarantee.

Getting a realistic number

Use race weight. Add the driver and fuel to the curb weight. Another 200 lb of driver is worth roughly a tenth or more at the strip.
Use crank horsepower. If you only know wheel horsepower from a dyno, pick the wheel-hp option in the calculator or use the WHP to HP converter.
Expect a gap on traction-limited cars. Front-wheel drive, street tires and manual launches usually run slower than the formula. The conservative figure shows how far that can go.
Weather matters. Hot, humid, high-altitude air makes less power. The formula assumes ordinary conditions.

Related quarter-mile tools

Need 1/8-mile numbers, a full time slip, or the horsepower required for a target ET? Use the 1/4 mile estimator, 1/8 mile ET calculator, dragstrip calculator or racing ET calculator.

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Frequently asked questions

How accurate is a quarter mile calculator?

It is a good planning tool when the inputs are right: crank horsepower and true race weight. Real results swing with traction, gearing, shift quality, weather and driver skill, so expect actual runs to land at or slower than the estimate on street cars.

What weight should I enter?

Enter the total weight as the car runs, which includes the driver, fuel and anything else on board. Using the curb weight alone makes the estimate too quick.

Does it work for EVs and motorcycles?

The math only needs power and weight, so it gives a reasonable first estimate. Electric cars deliver torque instantly and motorcycles are limited by launch and wheelie control, so use the result as a rough guide.

Is the 1/4 mile time the same as 0–60?

No. 0–60 mph measures a short, launch-dominated sprint, while the quarter mile is 1,320 ft and also rewards sustained power. Try the 0–60 calculator for that number.

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