Critical Power Calculator
Estimate CP, WPrime and the power curve for different durations from two all-out tests.
| Time | Predicted power | Use |
|---|---|---|
| 30 sec | 1153 W | Late sprint and short-hill attacks |
| 1 min | 713 W | Short climbs and attacks |
| 3 min | 420 W | VO2max intervals |
| 5 min | 361 W | Max aerobic power |
| 12 min | 310 W | Medium-long intervals |
| 20 min | 295 W | FTP test reference |
Monod & Scherrer (1965) first observed a hyperbolic relationship between power output and time to exhaustion in muscle groups, proposing the Critical Power model: work above CP consumes WPrime, a finite anaerobic work capacity, so higher power can be sustained for less time. Skiba et al. (2012) extended WPrime into a real-time "balance" model tracking depletion and recovery, useful for analyzing remaining anaerobic capacity after repeated attacks in a race. The two-parameter model is P = CP + WPrime / t. It is better than a single FTP value for planning 30-second to 12-minute intervals and race attacks.
Sources: Monod & Scherrer 1965, Ergonomics 8(3):329-338, Skiba et al. 2012, Med Sci Sports Exerc