How it works
FTP = 0.95 × best 20-minute average power
Functional Threshold Power is the highest power you could sustain in a quasi-steady state for about an hour. Testing for a full hour is brutal and rarely repeatable, so Allen and Coggan popularised a 20-minute field test: ride 20 minutes as hard as you can hold evenly, take the average power, and multiply by 0.95. The 5% haircut accounts for the fact that a 20-minute effort sits slightly above true one-hour power. Your watts-per-kilogram (FTP ÷ body weight) is what actually moves you up a climb — two riders with the same FTP but different weights climb at very different speeds, which is why the Coggan power-profile chart is plotted in W/kg. The seven training zones are simply percentage bands of FTP: everything from active-recovery spinning below 55% up to neuromuscular sprints above 150%.
Sources
- FTP and the 20-minute test Allen, H. & Coggan, A. (2010). Training and Racing with a Power Meter (2nd ed.). VeloPress. FTP ≈ 0.95 × 20-minute average power.
- Coggan power-training zones Coggan, A. — seven-zone power model: Active Recovery (<55% FTP), Endurance (56–75%), Tempo (76–90%), Threshold (91–105%), VO₂max (106–120%), Anaerobic (121–150%), Neuromuscular (>150%).
- Coggan power-profile chart Coggan, A. — power-profile tables expressing threshold and short-duration power in W/kg, from untrained through world-class.
FAQ
How do I run a 20-minute FTP test?
After a thorough warm-up (including a few short hard efforts), ride 20 minutes as hard as you can sustain at an even effort — pacing matters, do not blow up in the first five minutes. Record your average power for the 20 minutes and enter it here; the calculator multiplies by 0.95 to estimate FTP.
Why multiply by 0.95 instead of using the 20-minute power directly?
FTP is defined as roughly your one-hour power. A maximal 20-minute effort is a bit higher than what you could hold for a full hour, so Allen and Coggan apply a 5% reduction (the ×0.95 factor) to bring the shorter test down to true threshold.
What is a good FTP in watts per kilogram?
On the Coggan scale, recreational riders sit around 2.5–3.0 W/kg at threshold, strong club riders 3.5–4.0, and elite road racers above 5.0 W/kg. Because climbing speed depends on power relative to weight, W/kg is a fairer comparison than raw watts.
What are the seven power zones for?
They translate your FTP into target watts for different workouts: Zone 2 endurance for long base rides, Zone 3 tempo, Zone 4 threshold intervals, Zone 5 VO₂max repeats, and Zones 6–7 for anaerobic and sprint work. The table shows each zone in watts from your FTP.
How often should I retest my FTP?
Every 4–8 weeks during a training block, or whenever your threshold intervals start to feel easy. FTP drifts with fitness, fatigue, heat and altitude, so retest under similar conditions to compare fairly.
Can I estimate FTP without a 20-minute test?
Yes — some riders use an 8-minute test (×0.90), ramp tests, or 60-minute race data. The 20-minute ×0.95 method is the most widely cited field standard, which is why this calculator uses it. Enter whatever 20-minute average power you have measured.
FTP from a 20-minute test is an estimate; true threshold varies with pacing, terrain, heat and tester fitness. The Coggan categories are population guides, not a verdict on you. General training information, not medical or coaching advice — clear hard testing with a physician if you have any cardiovascular concern.