0-100 km/h Time from Power and Weight
Rule-of-thumb acceleration estimate in seconds from engine power in HP and kerb weight in kg: t = (kg/HP)^0.75 x 0.85. Not a track figure.
0-100 (s)
—
0-100 km/h acceleration: estimating launch time
A handy approximation is t ≈ (weight × V_f) / (HP × k). What dominates the result is the power-to-weight ratio. A Bugatti Chiron (1,500 HP, 1,995 kg) reaches 100 km/h in about 2.4 s, a Porsche 911 Turbo S does it in roughly 2.7 s, and a 1.0-litre hatchback popular in Brazil needs close to 14 s. All-wheel drive shaves time off a 2WD car because grip is what caps the launch, and RWD or FWD cars just spin the tires off the line. Launch Control handles clutch slip and revs so the getaway is clean. You can apply the same reasoning to 0-200 km/h and to the classic quarter-mile (1/4 mi, ~402 m) drag-race number.
Applications
Reading magazine spec sheets (Quatro Rodas, Top Gear), running comparison tests, racing simulators, drag-race videos, scoping out a supercar before buying, and homework on Newtonian mechanics that factors in rolling resistance.
FAQ
Why is power-to-weight the key number? Acceleration comes down to force ÷ mass, and engine power is what produces the force. So a car with a lower kg/HP figure launches quicker than one chosen on raw HP alone.
Does AWD always win at the line? Up to 100 km/h it usually does, since it lays all the torque down on the road. Past 150-180 km/h, though, the extra weight of the drivetrain starts working against you.
Why is the figure only approximate? A real launch hangs on tire grip, gearbox response, ambient temperature, the fuel and the driver. The formula sees none of that, so treat the number as a ballpark.
Related Tools
Epidemic Incidence per 100k
Calculates incidence rate per 100k from new cases and at-risk population.
BTU (AC) Calculator
Calculate the ideal BTU/h power for a room — based on area, people, electronics and sun exposure. Everything in your browser.
Power-to-Weight Ratio Calculator (kg/HP)
Weight in kg divided by engine output in HP: 12 is an economy car, 8 a hot hatch, 4 to 6 a sports car, near 1 a Formula 1. Lower means quicker.
Power Calculator
Calculate the power aⁿ of any base and exponent, including negatives and decimals. Shows the result in scientific notation when necessary.
Disease Prevalence per 100k
Calculates disease prevalence per 100k from total cases and population.
Junction Temperature
Calculate the junction temperature of a power semiconductor, T_j = T_a + P × R_th, from the ambient temperature T_a, the dissipated power P and the total junction-to-ambient thermal resistance R_th (°C/W). The result, in °C, is the device's internal temperature (silicon junction), which must not exceed the manufacturer's limit (typically 150 °C) on pain of failure. The thermal resistance adds the junction-to-case, case-to-heatsink and heatsink-to-ambient stages. Lowering R_th (larger heatsink, ventilation, thermal paste) lowers the junction temperature. It is the central calculation of power electronics thermal design. Enter the ambient temperature, the dissipated power and the thermal resistance.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.