Estimate the cycling power you should be able to sustain for any duration from your VO2max. Includes VO2 on-kinetics correction for short efforts, gross-efficiency input (default 20%), RER substrate adjustment, an uncertainty band, and a calibration mode that back-solves efficiency from a known FTP. Coggan profile shows where your number sits.
VO2max comes from a lab test (gold) or a 5–6 min all-out effort with HR (proxy). Pick a duration; we’ll preset a fraction-of-VO2max and efficiency that match. Override any field to explore.
If you know your FTP or 20-min mean max power from a real test, we’ll work backward to find the gross efficiency that matches. That value gets pushed into the main calculator.
| Level | 5 s | 1 min | 5 min | FTP |
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Five components turn VO2 into watts.
VO2 (L/min) = ml/kg/min × mass / 1000
Then × kJ/L oxygen (depends on RER) gives the kJ/min you’re burning at full VO2max.
kJ per liter of O2 depends on what you’re burning: ~19.6 kJ/L on pure fat (RER 0.70), ~21.1 kJ/L on pure carb (RER 1.00). Linearly interpolated. Race-pace cycling typically RER 0.92–0.98.
You can’t hold 100% of VO2max for long. The fraction drops with duration: ~95% at 5 min, ~85% at 20 min (FTP), ~80% at 60 min, ~72% at 3 hr. Auto-set by the duration dropdown.
For durations ≤ 180 s, the mean VO2 over the effort is reduced by the time it takes O2 to ramp up. Mono-exponential, τ = 30 s. Matters most for 5K-track-pace efforts; negligible past ~3 min.
Cycling efficiency converts metabolic kJ into pedal-stroke work. Typical 18–24%, higher for trained cyclists. Calibrate from a known 20-min FTP to lock in your real value.
This calculator turns a measured VO2max into a power target. Three real uses:
Calibration matters most. The default 20% efficiency is a population average. Your efficiency might be 18 or 23, that’s a 25% spread on output. If you have a verified FTP, run the calibrator first; the rest of the predictions come out much tighter.
Three maximal efforts → CP + W'. Cross-check the FTP this calculator predicts against a CP fit.
Open → Gear × Speed × PowerOnce you have a power target, project speed on your bike + course profile.
Open → All calculatorsBack to the full catalog, 30+ endurance calculators across performance, fueling, swim, bike, run.
Browse →The lab measures both directly, the two inputs that matter most for this calculator. One morning, gas analysis with cycling ramp protocol, you walk out with VO2max, ventilatory thresholds, and gross efficiency. Plug all three in here and the predictions tighten dramatically.
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