Why is FTP 95% of 20-minute power?

FTP is the highest power you could sustain for roughly an hour. A maximal 20-minute effort is slightly above that hour pace, so multiplying by 0.95 corrects the short test down to a true one-hour threshold estimate.

How do I do the 20-minute test?

Warm up well, then ride as hard as you can sustain evenly for 20 minutes, ideally after a short opener effort. Record the average power and enter it here. A steady pacing strategy gives the most accurate result.

It depends on weight, so power-to-weight (W/kg) matters more than raw watts. Recreational riders are often around 2 to 3 W/kg, strong amateurs 3.5 to 4.5, and elite road racers above 5.5 W/kg at threshold.

What are the 7 zones used for?

Each Coggan zone targets a different system: Zone 2 builds aerobic base, Zone 4 raises threshold, Zone 5 develops VO2max, and Zones 6 to 7 train anaerobic and sprint power. Structured plans rotate through them.

Do I need a power meter?

Yes. FTP is defined in watts, so you need a power meter or a smart trainer that reports power. Heart rate alone cannot give an accurate FTP because it lags effort and drifts with fatigue and heat.

Cycling FTP Calculator

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Cycling FTP calculator

Functional Threshold Power (FTP) is the cornerstone metric of structured cycling training — the highest power you can sustain for about an hour. This calculator estimates it from the most common field test, your best 20-minute average power, and then builds all seven Coggan training zones in watts so you can train at the right intensity for every session.

How it works

A maximal 20-minute effort is slightly harder than your true one-hour power, so the standard correction is:

FTP = 0.95 × (20-minute average power)

Each Coggan zone is then a fixed percentage band of FTP — for example Endurance is 56–75% and Threshold is 91–105%. The tool multiplies your FTP by each band’s bounds to give exact wattage ranges. If you enter your body weight it also reports power-to-weight in W/kg, the number that best predicts climbing and racing performance.

Tips and example

A rider averaging 280 W for 20 minutes has an FTP of 0.95 × 280 = 266 W. At 75 kg that is about 3.5 W/kg. Pace the test evenly — going out too hard inflates early watts and then fades, lowering your average. Re-test every 4 to 6 weeks of focused training to keep your zones honest.

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