How accurate are these estimates?

This is a typical-ratio estimate, not a measured power-duration curve. It applies fixed fractions of your FTP at each duration. Individual variation is significant — sprinters will have higher short-duration power relative to FTP, while time triallists may sustain higher fractions of FTP for longer. For a personalised curve, use 2+ maximal test efforts and fit a critical-power (CP) and W′ model.

What is the power-duration curve?

The power-duration curve shows the maximum power you can sustain for any given duration. Power decreases as duration increases, following a hyperbolic relationship.

Why does it use FTP as the basis?

FTP (Functional Threshold Power) is the most commonly tested metric and provides a good anchor point for estimating power at other durations.

How can I get more accurate values?

Perform dedicated maximal efforts at each duration (5s, 1min, 5min, 20min, 60min) and record the data with a power meter.

BikeCalcs

Power Duration Calculator — Sustainable Power Estimates

Estimate sustainable power output for different durations.

FTP

Functional Threshold Power in watts

Body Weight

Your body weight, used to express each power figure in watts per kilogram (W/kg)

How We Calculate This

Power-Duration Estimation

This calculator uses typical power-duration ratios relative to FTP:

5-second (neuromuscular): ~250% of FTP
1-minute (anaerobic capacity): ~140% of FTP (typically 120–150%; sprinters and track pursuiters run higher)
5-minute (VO2 max): ~120% of FTP
20-minute: ~105% of FTP (the inverse of the FTP = 0.95 × 20-minute power rule)
60-minute (FTP): ~100% of FTP — FTP is, by definition, the power you can hold for roughly an hour
2-hour: ~85% of FTP

Frequently Asked Questions

Related Calculators

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CdA Calculator

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Last updated: February 2026

All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.