Power to Weight Ratio Calculator
Enter power and weight in the units you have. The calculator reports the ratio in every common form so you can compare vehicles or riders.
Result
- Horsepower per US ton
- 171.4 hp/ton
- Kilowatts per tonne
- 140.9 kW/t
- PS per tonne
- 191.6 PS/t
Formula
- Power to weight = power ÷ weight
- Weight to power = weight ÷ power
- 1 hp = 745.7 W · 1 PS = 735.5 W · 1 lb = 0.4536 kg
How the Power to Weight Ratio Calculator works
Power to weight ratio is the best single predictor of straight-line acceleration. Two vehicles with the same ratio accelerate similarly even if one is much heavier and more powerful.
Car reviewers often quote pounds per horsepower, where lower is better, or horsepower per ton. Cyclists use watts per kilogram, where a sustained 4 W/kg marks a strong amateur.
Worked example
A 300 hp car weighing 3,500 lb has 300 ÷ 3,500 = 0.0857 hp per pound, or 11.67 lb per horsepower. In metric terms that is 223.7 kW over 1,587.6 kg, or 140.9 W/kg.
Frequently asked questions
What is a good power to weight ratio for a car?
Ordinary family cars are around 15 to 20 lb per hp. Sports cars are near 10, and supercars are 5 or lower.
How do I improve power to weight ratio?
Add power or remove weight. Removing 10 percent of the weight has the same effect on the ratio as adding 11 percent more power.
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Calculations run in your browser and nothing you enter is sent to a server. Results are provided for general information. Check critical figures independently before relying on them.