Power-to-Weight Ratio Calculator
Calculate your car’s power-to-weight ratio in hp/tonne and kW/kg — the single best measure of raw performance.
Power-to-Weight Calculator
HP or kW ÷ kg or lb
How It Works
Power-to-weight ratio divides engine output by vehicle mass. Higher values directly predict acceleration performance independent of vehicle type. It is more useful than absolute power figures alone.
How to Use This Calculator
- Enter your car's power in HP or kW.
- Select the power unit.
- Enter the vehicle weight (use kerb weight + driver + fuel).
- Select the weight unit.
- Click Calculate — see ratios and a performance class.
Worked Example
Reference Table
| Category | hp/tonne | Example |
|---|---|---|
| Economy car | 60–90 | Toyota Yaris, VW Polo |
| Family sedan | 100–130 | Toyota Camry, Honda Accord |
| Sport compact | 150–200 | Honda Civic Si, Ford Focus ST |
| Performance | 200–300 | BMW M3, Subaru WRX STI |
| Supercar | 300–500 | Porsche 911 GT3, Ferrari 458 |
| Hypercar | 500–1000 | Bugatti Chiron, Koenigsegg |
| Formula 1 | ~1400 | Modern F1 (power unit only) |
Frequently Asked Questions
Why is power-to-weight ratio more useful than absolute horsepower?
A 500 hp Dodge Viper (1 550 kg) and a 500 hp Toyota Tacoma (2 100 kg) have the same power but very different acceleration. PTW (323 vs 238 hp/tonne) correctly predicts the Viper is significantly quicker.
Should I use kerb weight or total weight?
For lap time prediction, use kerb weight + driver. For drag strip ET, use full race weight including driver and fuel. Manufacturers quote kerb weight (no occupants, standard fluids).
What power-to-weight ratio is needed for a 10-second quarter mile?
Approximately 350–400 hp/tonne or 0.26–0.29 kW/kg for a well-prepared street car with good traction. Launch control and gear ratios also significantly affect elapsed time.
How do electric vehicles compare on power-to-weight?
EVs often have excellent PTW ratios. Tesla Model S Plaid delivers ~1 000 hp from a 2 162 kg car = 463 hp/tonne, competitive with true supercars. Instant full torque delivery amplifies the advantage.
