Critical Power Calculator

Critical Power Calculator for Cycling
Cycling performance tool

Critical Power Calculator

Critical Power (CP) is a scientifically validated threshold that separates sustainable aerobic work from efforts that draw on your finite anaerobic reserves (W′). Unlike FTP — which estimates one hour’s effort — CP is derived from multiple maximal efforts across different durations, giving a more complete picture of your physiology.

Run two or three maximal efforts, enter your average power for each, and the calculator produces your CP, your W′ and your personalised 7-zone training framework.

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Complete 2–3 maximal efforts at different durations
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Enter duration and average power
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Get CP, W′ and training zones
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Critical Power Calculator
2-parameter model · CP + W′ · 7 training zones
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Critical Power (CP)
The highest power you can sustain aerobically without depleting finite anaerobic reserves.
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W′ — W prime
Your finite work capacity above CP. Once spent, power must drop below CP to recover it.
Zone% of CPWatts
2-parameter linear work-time model: W = CP × t + W′, ordinary least squares (Moritani et al., 1981; Whipp et al., 1982; Monod & Scherrer, 1965). Zones: Skiba (2006); Poole, Burnley, Vanhatalo, Rossiter & Jones (2016) Med Sci Sports Exerc 48(11).
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Work with a coach

Your zones are set. Now train in them with purpose.

Critical Power zones are only as powerful as the sessions built around them. Our coaches use your CP and W′ to structure sessions that build your aerobic ceiling, extend your anaerobic capacity and develop your ability to go deep and recover — exactly the qualities that win bike legs and set up strong runs.

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No obligation — just a conversation about where you are and where you want to get to.

Model: Moritani et al. (1981); Whipp et al. (1982); Monod & Scherrer (1965). Zones: Skiba (2006); Poole, Burnley, Vanhatalo, Rossiter & Jones (2016) Med Sci Sports Exerc 48(11).