FTP Calculator
Estimate your cycling Functional Threshold Power from a 20-minute test and get your seven Coggan training power zones in watts.
How it works
FTP = 20-minute average power × 0.95 · zone bounds = FTP × zone percentage
FTP is the highest power you could sustain for roughly an hour, and it anchors every structured cycling plan. Testing a true hour is brutal, so the standard field test rides an all-out 20 minutes and takes 95% of that number — the 5% haircut accounts for the extra intensity a 20-minute effort allows over a full hour. Once you have FTP, Dr Andrew Coggan’s seven zones fall out as fixed percentages of it.
Worked example
A 20-minute test averaging 250 W gives FTP = 250 × 0.95 = 237.5 ≈ 238 W. Endurance Zone 2 (56–75%) then runs about 133–178 W, threshold Zone 4 (91–105%) about 216–249 W, and VO2max Zone 5 (106–120%) about 252–285 W.
Frequently asked questions
Why multiply by 0.95 instead of using the 20-minute number?
Because you can push harder for 20 minutes than for a full hour. FTP is defined at roughly one hour, so the 5% reduction estimates the power you could actually hold for that longer duration.
How often should I retest?
Every 4–6 weeks of focused training, or after a clear fitness change. Retesting too often adds fatigue without new information; too rarely and your zones drift out of date.
Is watts-per-kilogram more important than raw FTP?
For climbing and racing, yes — power-to-weight decides who drops whom on a hill. Raw FTP matters more on the flat and in time trials. Use both; a power-to-weight calculator turns your FTP into W/kg.
Related calculators
Estimates for general fitness and education — individual results vary with terrain, fitness, technique and measurement error. Not medical advice.