Quarter Mile & 0-60 Converter
Convert between quarter-mile ET, trap speed, 0-60 time and horsepower for any vehicle weight.
Enter a weight and one known figure — everything else is estimated as you type.
- Engine power (flywheel)
- —
- Quarter-mile ET
- —
- Trap speed
- —
- Eighth-mile ET
- —
- 0–60 mph
- —
- 0–100 km/h
- —
- Power-to-weight
- —
These are estimates for a healthy car on a prepared surface at sea level, using flywheel (crank) horsepower and race weight including the driver. Traction, gearing, altitude, drivetrain loss, aerodynamics and driver skill easily move a real run by half a second. Trap speed is the most reliable of the three — it barely cares how well you launched.
How it works
Drag-racing maths hangs on one relationship: elapsed time and trap speed scale with the cube
root of the weight-to-power ratio. This tool uses Roger Huntington's classic
pair — ET = 5.825 × (weight ÷ hp)1/3 and
MPH = 234 × (hp ÷ weight)1/3 — with weight in pounds and flywheel
horsepower. Switch to the Fox variant (constants 6.290 and 224) if you prefer
the slightly more conservative numbers most street cars actually run. Both are invertible, so
giving the tool a timeslip instead of a dyno sheet works just as well:
hp = weight ÷ (ET ÷ 5.825)³ and hp = weight × (MPH ÷ 234)³.
The eighth mile uses the standard bracket-racing ratio 1/4 ET = 1/8 ET × 1.55. The
0–60 mph figure comes from an empirical power-law fit to published road tests,
ET ≈ 7.4 × t0-600.375, inverted as
t0-60 = (ET ÷ 7.4)8/3; it lands within a couple of tenths for
normal cars but flatters very grippy AWD and EV launches. 0–100 km/h is the 0–60 time × 1.05,
the usual rule of thumb (100 km/h is 62.1 mph, and those last 2 mph take a little longer than
average). Everything runs in your browser in plain JavaScript — no uploads, no sign-up, no ads.
Frequently asked questions
How do you estimate horsepower from a quarter-mile time?
Invert Roger Huntington's classic formula: hp = weight ÷ (ET ÷ 5.825)³, with weight in pounds including the driver. A 3,400 lb car running 13.2 seconds works out at about 292 flywheel horsepower. Trap speed gives a steadier answer, because hp = weight × (mph ÷ 234)³ barely depends on how well the car launched.
What 0-60 time matches a 13-second quarter mile?
About 4.6 seconds. This tool uses an empirical power-law fit to published road tests, ET ≈ 7.4 × t₀₋₆₀^0.375, inverted as t₀₋₆₀ = (ET ÷ 7.4)^(8/3). It is accurate to a couple of tenths for normal cars, but very grippy all-wheel-drive and electric launches beat it because they get off the line far harder than a typical rear-drive car.
How do I convert an eighth-mile time to a quarter-mile time?
Multiply by 1.55 — the standard bracket-racing ratio. An 8.50-second eighth mile is roughly a 13.2-second quarter, and going the other way you divide the quarter-mile ET by 1.55. It is a rule of thumb: cars that keep pulling hard at the top end beat it, and traction-limited or short-geared cars fall behind it.