0-60 mph from Power-to-Weight Calculator
Estimate a car’s 0-60 mph time from its horsepower and weight using a constant-power model with a real-world traction factor.
How it works
Ideal time = m × v² ÷ (2 × P) · Estimated time = ideal ÷ usable-power fraction · m = weight in kg, v = 60 mph = 26.82 m/s, P = power in watts (1 hp = 745.7 W)
A constant-power model gives the physical floor for acceleration: the energy needed to reach 60 mph divided by the power available. Real cars never hit that floor — off the line they are traction-limited, lose time to gearshifts, and turbos take a moment to spool — so a "usable power fraction" scales the ideal up to a realistic figure (around 50% for a typical performance car). Power-to-weight is the single best predictor: lighter cars with more power accelerate harder regardless of badge.
Worked example
A 3,300 lb car (1,497 kg) with 300 hp (223.7 kW): the ideal time is 1,497 × 26.82² ÷ (2 × 223,700) ≈ 2.4 s. Delivering about 50% of that power off the line puts the realistic 0–60 near 4.8 seconds — matching a 300 hp, ~11 lb/hp sports sedan.
Frequently asked questions
Why is the real 0-60 slower than the physics ideal?
The ideal assumes full power the instant you launch, which no car manages. Tires spin, weight transfers, gears must be shifted, and turbos lag — all of which waste time. The usable-power fraction captures those losses; higher-grip, all-wheel-drive launches use a larger fraction.
What usable-power fraction should I use?
Around 45–55% suits a typical rear- or front-drive performance car. A sticky-tired, launch-controlled all-wheel-drive car may effectively use 60–70%, while a low-grip or turbo-laggy setup may be nearer 40%. Adjust it to match a known car, then compare others.
Is power-to-weight really the main factor?
For straight-line acceleration, yes — it sets the fundamental limit. Traction, gearing, aerodynamics and drivetrain type then decide how much of that potential reaches the road, but two cars with very different weights and powers but the same lb/hp will accelerate similarly.
Related calculators
Educational estimate — real-world figures vary with load, temperature, traction, tuning and measurement method.