0-60 mph Calculator: Estimate Acceleration From Weight and Horsepower
Estimate a car's 0-60 mph and 0-100 km/h time from weight and horsepower, with drivetrain, gearbox, tires, wet roads and magazine rollout, or find the horsepower needed for a target time. Includes times to 30-100 mph, quarter mile and traction limit.
How it works
a = min(μ × g × driven-wheel share, P_use ÷ (m × v)) − (½ρ·CdA·v² + Crr·m·g) ÷ m · P_use = P_crank × (1 − drivetrain loss) × power-band factor · t = ∫ dv ÷ a from 0 to 60 mph + shift time − rollout
A car accelerating from rest is first limited by grip: the tires can push only so hard before they spin, which works out to about 0.6 g for front-wheel drive, 0.7 g for rear-wheel drive and 1 g for all-wheel drive on all-season tires, about 20% more on performance tires and about 30% less on a wet road. Once the speed rises, power becomes the limit, because the force the engine can deliver is power divided by speed. The calculator works through the run in small speed steps, taking the lower of the two limits and subtracting air drag and rolling resistance, then adds a little time for gear changes. Not all of the rated power reaches the road: the drivetrain loses about 12% (FWD) to 18% (AWD), or about 10% in an electric car, and the engine is not at peak power the whole time; the power-band factor (0.65–0.85 by gearbox) covers this. Those factors were tuned so the results match published instrumented 0–60 tests of about sixteen current cars within about 9% on average, against about 19% for the old 0.87 × (lb/hp)^0.75 rule, which is still shown for comparison. US magazines subtract a 1-foot rollout, which is on by default; switch it off to compare with European 0–100 km/h figures. Use "Power needed" to find the crank horsepower for a target time; if the tires are the limit, no amount of power will get there. The model does not know about launch control, turbo lag, gearing, tire temperature or altitude, so treat the result as an estimate with a range of roughly ±10%.
Worked example
A 3,300 lb rear-wheel-drive car with a 150 lb driver (3,450 lb, 1,565 kg), 250 hp and an automatic on all-season tires: usable power is 250 × 745.7 W × (1 − 15%) × 0.70 = 110.9 kW and the grip limit is 1.00 × 0.72 = 0.72 g. Power alone would need 1,565 × 26.82² ÷ (2 × 110,900) = 5.07 s. Grip limits the first 22 mph or so, drag and rolling resistance take a little more, and gear changes add 0.05 s; with the 1-ft rollout removed the estimate is 5.9 s to 60 mph (likely range 5.3–6.5 s), about 6.3 s to 100 km/h, 0.47 g on average over 327 ft. The simple rule gives 6.2 s for the same weight.
Sources: Rollout in timed acceleration runs (Wikipedia) · Kinetic-energy 0–60 method (calculate.co.nz) · 0–60 time factors: drivetrain, tires, conditions (Omni Calculator)
Frequently asked questions
How accurate is a 0–60 estimate from horsepower and weight?
For ordinary road cars this model usually lands within about 10% of magazine times. It is least reliable for very powerful cars, where launch control and tires decide the result, and for cars whose spec-sheet power is understated or overstated.
Why does all-wheel drive help so much?
At launch, the tires can only push with a force of about the weight they carry times the grip. AWD uses all four tires, so it can pull close to 1 g, while a front-wheel-drive car gets about 0.6 g because weight shifts off the front wheels as it accelerates.
Should I use crank or wheel horsepower?
Use the figure you have and pick the matching option. Spec sheets give crank (engine) power; a chassis dyno measures wheel power, which is about 12–18% lower for gasoline cars because of drivetrain losses.
What is rollout and why do magazine times look quicker?
US magazines start the clock after the car has moved one foot, copying how drag strips time runs. That trims about 0.2–0.3 s from 0–60, so a GPS timer started from rest, or a European 0–100 km/h figure, usually reads slower.
How much horsepower do I need for a 4-second 0–60?
Switch to "Power needed" and enter 4 s. For a 3,300 lb rear-drive automatic with a 150 lb driver the model asks for about 445 hp on all-season tires, about 380 hp on performance tires and about 375 hp with AWD, because better grip wastes less of the launch.
What is a good power-to-weight ratio?
Everyday cars sit around 100–150 hp per ton (13–20 lb/hp), sporty cars 200 hp per ton or more (under 10 lb/hp) and supercars 300+ hp per ton. Below about 6 lb/hp, 0–60 under 4 s is possible if the tires can use the power.
Related calculators
Educational estimate. Real-world results vary with conditions, tuning and measurement.