Native tool · INT.02 Build · runs on this page
Power-to-Weight Calculator
Horsepower sells cars; kg per hp predicts how they move. Enter power and weight, pick a load factor, and read the number that matters.
Power-to-Weight · v1.0
Lower = fasterRule of thumb: under 5 kg/hp feels genuinely fast; under 3 is supercar territory.
Why this number matters
Power-to-weight is the great equalizer. A 200 hp car at 900 kg will walk away from a 300 hp car at 1,800 kg — and this ratio is why spec-sheet horsepower keeps misleading buyers. It's also the honest way to judge a modification: removing 50 kg often beats adding 20 hp, and it's usually cheaper.
We calculate in kg per hp because it reads at human scale — every 0.5 you shave off is a change you can feel. Prefer hp per tonne? Divide 1000 by your result.
Reference classes
| kg / hp | hp / tonne | Feels like | Typical of |
|---|---|---|---|
| < 3.0 | 333+ | Violent | Supercars, superbikes |
| 3.0–5.0 | 200–333 | Seriously quick | Sports cars, hot hatches+ |
| 5.0–8.0 | 125–200 | Brisk | Warm hatches, older sports cars |
| 8.0–12.0 | 83–125 | Everyday | Most modern cars |
| 12.0+ | < 83 | Leisurely | Economy cars, vans |
FAQ
Both express the same ratio. kg/hp reads intuitively at car scale: lower is faster, and one unit of change is meaningful. Divide 1000 by kg/hp to get hp per tonne.
Loaded. You never lap at curb weight — add driver, fuel and gear. The load factor in this tool approximates that for you.
For acceleration feel, usually yes. A light car with modest power often out-accelerates a heavy car with big numbers. Aero, gearing and traction still matter.
