0-60 Time Calculator

This calculator turns three numbers — the car's weight with a driver on board, the horsepower that reaches the wheels and the drivetrain layout — into an estimated 0-60 mph time, a 0-100 km/h time, pounds per horsepower and horsepower per metric tonne. It is useful for comparing a planned power upgrade against a weight reduction, or for sanity-checking a claimed time for a project car.

The model is deliberately simple. It knows nothing about gearing, tires, launch control or shift speed, so treat the result as a conservative baseline: modern cars with quick-shifting automatics and launch control often beat it, sometimes by more than a second. Older manual cars on street tires usually land closer to it.

If you only know torque and rpm from a dyno sheet, convert them first with the horsepower from torque calculator. To see how gearing changes things, the gear ratio calculator shows road speed in each gear.

This is an empirical rule of thumb, not a physics simulation. Acceleration in a straight line depends on power-to-weight, but the exponent below 1 and the drivetrain factor stand in for traction limits and gear changes. A full estimate would integrate tractive force through each gear, which needs the torque curve, gear ratios and tire grip (see Gillespie's vehicle dynamics text). The hp-per-tonne figure uses 2,204.6 lb per metric tonne.

The table runs the calculator's formula at common power-to-weight ratios. Use it to see how much a change is worth: going from 12 to 10 lb/hp saves roughly 0.9 seconds in a rear-drive car, while going from 20 to 15 lb/hp saves about 2 seconds.

• One-foot rollout: many US magazines start the clock after the car has already moved about a foot, mimicking a drag strip. That trims a few tenths from the time.
• Launch control and fast gearboxes: dual-clutch and modern automatic transmissions shift in a fraction of a second and hold the engine at the ideal launch rpm.
• Gearing: a car that reaches 60 mph in second gear avoids a shift that one needing third gear has to make.
• Tires and surface: sticky tires on a prepared surface launch harder than all-season tires on cold asphalt.
• Air density: heat, humidity and altitude cut the power of non-turbo engines; turbocharged engines are affected less.

Manufacturers quote crank (brake) horsepower, measured at the engine under standards such as SAE J1349. This calculator asks for wheel horsepower, which is what a chassis dyno measures after the gearbox, driveshaft and differential have taken their share. A common rule of thumb is that wheel horsepower is roughly 10–20% below the crank figure, with AWD and older automatics at the higher end of that range. If you only have the brochure figure, reduce it by about 15% before entering it.