Calculate Your Critical Power (CP)
Sports training combines physiology, biomechanics, and structured programming. Training intensity zones, weekly load management, and proper recovery form the foundation of athletic performance. This calculator determines your critical power (CP) and W' capacity from two time-trial efforts—typically a 3-minute and 12-minute all-out test. Free, fast, and updated for 2026.
When to use this calculator
- Technical calculations for critical power analysis
- Coaches and sports science students
- Validate theoretical results before training implementation
- Teaching and learning exercise physiology concepts
- Quick reference for personalized training design
Example Calculation
- 400W×180s, 320W×720s
- CP = 293 W, W' = 19,280 J
How it works
1 min readSports training integrates physiology, biomechanics, and practice. Training intensity, progressive load, rest, and nutrition work together as a complete system.
How CP Is Calculated
Critical power represents the maximum power you can sustain indefinitely without fatigue accumulation. The 2-parameter model uses two maximal efforts at different durations to solve for both CP (the sustainable threshold) and W' (the finite anaerobic energy reserve that depletes above CP).
Typical test efforts are a 3-minute all-out effort and a 12-minute all-out effort. The calculator applies the standard formula with your input values, checking for reasonable ranges and alerting if values fall outside typical parameters.
How to Use This Calculator
Perform two maximal time trials at different durations (e.g., 3 minutes and 12 minutes). Record your average power output (in watts) for each effort along with the duration. Enter these values and the calculator will determine your CP threshold and anaerobic capacity.
Final Notes
This calculation is a reference estimate. For critical decisions (medical, coaching, competition strategy), consult a qualified sports science professional. Values are current as of 2026 and reviewed periodically.
Frequently asked questions
What is critical power (CP)?
Critical power is the maximum power output you can maintain indefinitely without fatigue accumulation. Below CP, effort is sustainable; above CP, you rely on finite anaerobic capacity.
How does the 2-parameter model work?
The model uses two maximal efforts at different durations. The curve fitting determines both your CP threshold and W' (anaerobic capacity). More mathematically robust than simple FTP estimates.
What's the difference between CP and FTP?
CP (critical power) is theoretically sustainable indefinitely with proper recovery. FTP (functional threshold power) is practical, representing ~1-hour max effort. CP is more physiologically precise; FTP is more training-pragmatic.
What is W' (W-prime)?
W' is your anaerobic capacity—finite energy available above CP. During hard efforts, you deplete W' quickly. Recovery below CP replenishes it within minutes.
How long does W' recovery take?
Complete W' recovery occurs during sustained efforts below CP, typically taking 2–5 minutes depending on intensity. Recovery is faster than glycogen depletion—measured in minutes, not hours.
What are typical CP values for cyclists?
Varies widely: recreational cyclists 150–250 W, competitive amateurs 250–400 W, elite cyclists 400+ W. Your body weight and sport experience both influence absolute power.
Is this calculator free and private?
Yes—all Hacé Cuentas calculators are free, no registration needed, and your data never leaves your browser. We don't store or transmit your inputs.
How accurate are these results?
Results are estimates using the standard 2-parameter model validated internationally. For critical coaching or medical decisions, work with a sports science professional and real power-meter data.