Power-to-weight ratio (PWR) measures how much power is available relative to vehicle mass. It is expressed as either lbs/HP (lower is better) or HP/ton (higher is better). A car with 400 HP and 4,000 lbs has 10 lbs/HP. PWR is the single best predictor of acceleration performance—two cars with the same PWR will have similar 0–60 times regardless of engine size.
- lbs/HP = Vehicle Weight / Horsepower (lower is faster)
- HP/ton = (Horsepower / Weight in lbs) × 2,000 (higher is faster)
- A Miata (2,300 lbs, 181 HP = 12.7 lbs/HP) accelerates like a 4,000 lb car with 315 HP
- Motorcycles dominate PWR: 600cc sportbike = ~2.5 lbs/HP vs sports car at ~7–8 lbs/HP
- Reducing weight by 100 lbs is equivalent to adding ~10–15 HP in a 3,500 lb car
| Vehicle Type | Typical lbs/HP | Typical HP/ton |
|---|---|---|
| Economy Car | 16–22 | 91–125 |
| Sports Sedan | 9–13 | 154–222 |
| Sports Car | 6–9 | 222–333 |
| Supercar | 3.5–6 | 333–571 |
| Sportbike (600cc+) | 2–4 | 500–1,000 |