Power to Weight Ratio Calculator
Enter a vehicle's power and weight to get its power to weight ratio in several common units, so you can compare cars across imperial and metric figures.
How to calculate power to weight ratio
- Enter the power in horsepower or kilowatts.
- Enter the weight in pounds or kilograms.
- Read the ratio in hp/lb, hp/ton, watts/kg and kW/tonne.
Examples
Sports sedan
300 hp, 3000 lb
0.10 hp/lb, 200 hp/ton
Same car in metric
223.7 kW, 1360.8 kg
164.4 watts/kg
Frequently asked questions
What is power to weight ratio?
It is engine power divided by vehicle weight. A higher ratio means more power for each unit of mass, which generally gives quicker acceleration.
How do I calculate power to weight ratio?
Divide power by weight in matching units. For hp per pound, divide horsepower by pounds; for watts per kg, divide power in watts by kilograms.
What is a good power to weight ratio for a car?
Everyday cars sit near 0.05 hp/lb, hot hatches around 0.08, and sports cars at 0.10 hp/lb or more. Supercars often exceed 0.20 hp/lb.
How do I convert horsepower to kilowatts?
Multiply horsepower by 0.745699872 to get kilowatts. This tool does the conversion so it can report watts per kg and kW per tonne alongside the imperial figures.
Should I use curb weight or with a driver?
Be consistent. Curb weight is the common baseline for spec comparisons, but adding driver and fuel gives a truer real-world figure. Use the same basis when comparing cars.
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