Power to Weight Calculator
Calculate a vehicle's power-to-weight ratio.
Power to weight
100bhp/tonne
- Power per kg
- 0.1 bhp/kg
v1.0 · Reviewed September 2026
How this is worked out
Power is divided by weight in tonnes, with a second line giving bhp per kilogram.
Worked example
- 150 bhp
- 1,500 kg
150 ÷ 1.5
100 bhp/tonne
Assumptions and limits
- Both figures must be consistent. Comparing a crank bhp figure with a kerb weight, as manufacturers do, is the usual convention.
- Kerb weight excludes passengers and luggage, which meaningfully change the ratio in a small car.
- A useful comparison figure, but gearing, traction and aerodynamics also determine how quick a car actually is.