How the estimate works
Quarter-mile ET and trap speed use the Huntington drag-racing relationships, which tie elapsed time and trap speed to power-to-weight and nothing else:
ET = 5.825 × (lb ÷ hp)⅓ · trap = 234 × (hp ÷ lb)⅓
Those cube roots are why chasing power gets expensive. To halve your ET you would need eight times the power — and why 100 kg out of the car is worth more than it looks on a spec sheet. 0–60 is estimated from the same ratio and adjusted for drivetrain: AWD hooks up and launches hardest, FWD unloads the driven wheels and spins soonest.
A worked example, and the numbers the tool gives for it: 300 hp in a 1,450 kg car is 10.7 lb/hp, which lands on a 12.82 s quarter at a 106 mph trap, and 5.9 s to 60 mph on a rear-drive launch.
Quarter-mile reference chart
Both tables are generated by running the calculator above, so a row here cannot disagree with the tool.
ET, trap speed and 0–60 by power-to-weight
Elapsed time and trap speed depend on nothing but the power-to-weight ratio, so one row covers every car that shares it. 0–60 is shown for a rear-drive launch.
| lb/hp | ¼-mile ET | Trap (mph) | 0–60 |
|---|---|---|---|
| 4.0 | 9.25 | 147 237 km/h | 2.2 |
| 4.5 | 9.62 | 142 228 km/h | 2.5 |
| 5.0 | 9.96 | 137 220 km/h | 2.8 |
| 5.5 | 10.28 | 133 213 km/h | 3.0 |
| 6.0 | 10.58 | 129 207 km/h | 3.3 |
| 6.5 | 10.87 | 125 202 km/h | 3.6 |
| 7.0 | 11.14 | 122 197 km/h | 3.9 |
| 7.5 | 11.40 | 120 192 km/h | 4.1 |
| 8.0 | 11.65 | 117 188 km/h | 4.4 |
| 9.0 | 12.12 | 112 181 km/h | 5.0 |
| 10.0 | 12.55 | 109 175 km/h | 5.5 |
| 11.0 | 12.95 | 105 169 km/h | 6.1 |
| 12.0 | 13.34 | 102 164 km/h | 6.6 |
| 13.0 | 13.70 | 100 160 km/h | 7.2 |
| 14.0 | 14.04 | 97 156 km/h | 7.7 |
| 15.0 | 14.37 | 95 153 km/h | 8.3 |
| 16.0 | 14.68 | 93 149 km/h | 8.8 |
| 18.0 | 15.27 | 89 144 km/h | 9.9 |
| 20.0 | 15.81 | 86 139 km/h | 11.0 |
| 22.0 | 16.32 | 84 134 km/h | 12.1 |
| 25.0 | 17.03 | 80 129 km/h | 13.8 |
Quarter-mile ET by power and weight
The same maths as a lookup grid, in the units you already have. Weight is with driver and fuel.
| Weight | 150 hp | 200 hp | 250 hp | 300 hp | 400 hp | 500 hp | 600 hp | 750 hp |
|---|---|---|---|---|---|---|---|---|
| 1,000 kg 2,205 lb | 14.27 | 12.96 | 12.03 | 11.32 | 10.29 | 9.55 | 8.99 | 8.34 |
| 1,100 kg 2,425 lb | 14.73 | 13.38 | 12.42 | 11.69 | 10.62 | 9.86 | 9.28 | 8.61 |
| 1,200 kg 2,646 lb | 15.16 | 13.78 | 12.79 | 12.03 | 10.93 | 10.15 | 9.55 | 8.87 |
| 1,300 kg 2,866 lb | 15.57 | 14.15 | 13.13 | 12.36 | 11.23 | 10.42 | 9.81 | 9.11 |
| 1,400 kg 3,086 lb | 15.96 | 14.50 | 13.46 | 12.67 | 11.51 | 10.69 | 10.06 | 9.33 |
| 1,500 kg 3,307 lb | 16.33 | 14.84 | 13.78 | 12.96 | 11.78 | 10.93 | 10.29 | 9.55 |
| 1,600 kg 3,527 lb | 16.69 | 15.16 | 14.08 | 13.25 | 12.03 | 11.17 | 10.51 | 9.76 |
| 1,700 kg 3,748 lb | 17.03 | 15.47 | 14.36 | 13.52 | 12.28 | 11.40 | 10.73 | 9.96 |
| 1,800 kg 3,968 lb | 17.36 | 15.77 | 14.64 | 13.78 | 12.52 | 11.62 | 10.93 | 10.15 |
| 2,000 kg 4,409 lb | 17.98 | 16.33 | 15.16 | 14.27 | 12.96 | 12.03 | 11.32 | 10.51 |
ET or trap speed — which one tells the truth?
They measure different things, and this is the single most useful idea on the page.
- Trap speed measures the engine. It is the speed at the end of the quarter, by which point the launch is long forgotten. Trap barely moves with traction, so it is the honest read on how much power the car actually makes.
- ET measures the whole run. Elapsed time includes the launch, the 60-foot, every shift and every wheelspin — so ET rewards a driver and a set of tyres as much as an engine.
That is why two cars can trap identically and finish a tenth apart, and why a tuner asks for your trap speed rather than your ET. If you already have a time slip, work backwards from it with the trap speed horsepower calculator — the same relationship, solved for power.
What the 60-foot time does to your ET
The first 60 feet is where a quarter-mile run is won or lost. A rough rule drag racers use: every 0.1 s off your 60-foot is worth roughly 0.2 s of ET, and that gain is nearly free — it costs tyre pressure and launch technique, not money.
Rough 60-foot benchmarks for a street car: 2.2 s or worse means you are spinning or bogging; 1.9–2.0 s is a decent street-tyre launch; 1.7 s needs a sticky tyre and a car that squats. This calculator assumes a competent launch for the drivetrain you pick — it cannot see your tyres.
Why the strip disagrees with the estimate
The formulas describe a car that puts its power down. Real runs differ, and almost always in the same directions:
- Traction. The biggest single variable. Street tyres on a cold, unprepped surface can cost half a second of ET that no amount of power buys back.
- Gearing. A car that has to shift right at the stripe, or that runs out of gear before it, loses time the formula never sees. Check yours with the gear ratio calculator.
- Air. A hot, humid, high day makes less power and more ET. Density altitude of 3,000 ft is worth several tenths — the density altitude calculator gives the number for your day.
- Which power figure you typed. Crank power matches these formulas. Wheel power does not, and will read optimistically fast.
- Weight. Kerb weight is not race weight. Driver, fuel, and whatever is still in the boot all count.
Expect the estimate to be close on a well-prepped car and optimistic on a stock one. Treat it as the number your car should run, and the difference as the size of your traction problem.
FAQ
Crank or wheel power?
Crank (flywheel) power — that is what the Huntington relationships were fitted to, and what manufacturers quote. If all you have is a chassis-dyno figure, add roughly 10–15% for a manual and more for an automatic or all-wheel drive before typing it in, or the estimate will flatter you.
Why include driver weight?
Because acceleration is about total moving mass, and the car does not know which part of it is you. Add 75–90 kg for driver and fuel. Leaving it out is the most common reason an estimate comes back optimistically quick.
How accurate is a quarter-mile estimate?
For a healthy, well-driven car on a decent surface, usually within about 2–3 tenths on ET and a few mph on trap. The estimate has no way to know your tyres, your gearing or your launch, so it describes the car's potential rather than a prediction of your next run.
What is a good quarter-mile time?
Rough street-car bands: under 17 s is ordinary, 15 s is warm, 13 s is genuinely quick, 12 s puts you into "you need a roll cage soon" territory at most tracks, and 11 s or better needs the car built for it. Trap speed is the better bragging number because it is harder to fake.
Is 0–60 mph the same as 0–100 km/h?
Nearly, but not quite — 100 km/h is 62.1 mph, so 0–100 km/h is always the slower figure, typically by 3–6%. European and US road tests are not directly comparable for that reason, which is why both are shown above.
Where to go next
Power-to-weight is the ratio all of this rests on — see it directly with the power-to-weight calculator. Working backwards from a real time slip is the trap speed calculator. And if you would rather run the quarter than calculate it, your saved car will launch down a simulated strip in Drag Race.