Power to Weight Ratio Calculator

It is engine power divided by vehicle weight. A higher ratio means more power carrying each unit of mass, which generally means quicker acceleration and livelier response.

It reports hp per pound, hp per ton, watts per kilogram and kilowatts per tonne together. For 300 hp and 3000 lb that is 0.1 hp/lb, 200 hp/ton, and 164.4 in both W/kg and kW/tonne.

Because a tonne is 1,000 kg and a kilowatt is 1,000 watts, the two thousandfold factors cancel exactly. Watts per kilogram and kilowatts per tonne are therefore always identical, just expressed at different scales.

Yes. The power and weight toggles are independent, so you can enter horsepower with kilograms or kilowatts with pounds. The engine converts each figure to the units it needs before dividing.

Multiply horsepower by 0.745699872 to get kilowatts. The tool uses this mechanical horsepower factor so its metric outputs line up with the imperial ones from a single entry.

Everyday cars sit near 0.05 hp/lb, warm hatches around 0.08, and sports cars from about 0.10 hp/lb upward. Many supercars pass 0.20 hp/lb, and the same ranking holds if you compare them in W/kg instead.

Be consistent across the cars you compare. Curb weight is the usual baseline for published specs, while adding driver, passengers and fuel gives a more realistic figure. Pick one basis and apply it to every vehicle.

The hp per ton output uses the US short ton of 2,000 pounds, while kW per tonne uses the metric tonne of 1,000 kilograms. They are different masses, so read each ratio with its own unit label.

No. The ratios are computed in your browser as you type, so the power and weight you enter never leave your device.