What Is a Cycling FTP Calculator?
Functional Threshold Power (FTP) is the highest average power, in watts, that a cyclist can sustain for approximately one hour. It's the central number used to set structured training zones, pace time trials, and track fitness gains over a season.
This calculator uses the most common field test — a 20-minute maximal effort — and applies the standard 0.95 multiplier to estimate the power you could hold for a full hour, since all-out 20-minute efforts are far easier to pace accurately than a full hour-long test.
How to Read Your Results
Estimated FTP
Your estimated one-hour sustainable power in watts. This is the number to plug into most cycling training apps (TrainerRoad, Zwift, TrainingPeaks) as your FTP setting.
Power-to-Weight (W/kg)
FTP divided by your body weight in kilograms. This is the standard way to compare cyclists of different sizes — it's especially predictive of climbing performance.
Endurance, Tempo & Threshold Zones
Training power zones set as percentages of FTP, following Andrew Coggan's widely adopted seven-zone model. Zone 2 (endurance) builds aerobic base at an easy, conversational effort; Zone 3 (tempo) is a moderately hard sustained effort; Zone 4 (threshold) sits right around your FTP itself.
Real-World Example
A 70 kg rider averages 250 watts over a 20-minute maximal test.
| Metric | Result |
|---|---|
| Estimated FTP | 250 × 0.95 = 238 W |
| Power-to-weight | 238 ÷ 70 = 3.40 W/kg |
| Endurance zone (Z2) | 133-179 W |
| Tempo zone (Z3) | 181-214 W |
| Threshold zone (Z4) | 217-250 W |
A W/kg of 3.40 places this rider in the "good" range for a recreational, fitness-focused cyclist, and gives them concrete wattage targets for each training zone.
Tips for Using This Calculator
- Warm up thoroughly (15-20 minutes) before an FTP test — a cold start will underestimate your true FTP.
- Pace evenly. Starting too hard and fading skews the average power lower than a truly sustainable effort.
- Retest every 6-8 weeks during a training block to keep your zones current as fitness changes.
- FTP is specific to cycling power meters — running FTP or other sport thresholds use different methods and aren't directly comparable.
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Last updated: August 2026 · Reviewed by: Simple Calculator Tools Editorial Team