Cycling FTP Test CalculatorFree online fitness & health calculator — instant results, no sign-up
Estimate functional threshold power from a standard 20-minute maximal test.
For general information only. This is not medical advice, diagnosis, dosing guidance or a treatment recommendation. Talk to a doctor or other qualified health professional about your health, pregnancy, or diet.
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About the Cycling FTP Test Calculator
The Cycling FTP Test Calculator estimates functional threshold power from your average power during a standard 20-minute maximal cycling test. It multiplies that power by a protocol adjustment factor to estimate a longer-duration threshold effort. With the default inputs of 260 W and 0.95, estimated FTP is 247 W.
- 20-minute average power (W)
- Your mean power over the full 20-minute maximal test, measured in watts (W), with a default of 260 W.
- Protocol adjustment factor
- A dimensionless multiplier used to convert 20-minute average power into estimated FTP, with a default of 0.95.
Formula and method
FTP_est = P_20 × f; with the defaults: 260 W × 0.95 = 247 W.
- FTP_estEstimated functional threshold power, in watts (W).
- P_20Average power over the complete 20-minute maximal test, in watts (W).
- fDimensionless protocol adjustment factor; 0.95 retains 95% of the test's average power.
The calculator multiplies the entered 20-minute average power by the protocol adjustment factor. It reports the product as estimated FTP in watts and includes a note explaining that the common 95% factor is approximate rather than an individualized physiological measurement.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- 20-minute average power260 W
- Protocol adjustment factor0.95
Results
- Estimated FTP247 W
- NoteThe common 95% factor is approximate and depends on test preparation and athlete.
How to use the Cycling FTP Test Calculator
- 1Follow a consistent 20-minute FTP test protocol, including its prescribed warm-up and preparation, using a properly calibrated power meter or smart trainer.
- 2Complete the 20-minute effort with the highest average power you can sustain across the full interval, aiming for controlled pacing.
- 3Enter the average power for that exact interval—not normalized power or the average for the entire ride; the default is 260 W.
- 4Use the default adjustment factor of 0.95 unless your testing protocol or an individualized assessment supports another factor.
- 5Read the estimated FTP and accompanying note; the default inputs produce 247 W.
Reading your result
Estimated FTP: 247 W is the threshold-power estimate calculated from the default 260 W test average and 0.95 factor. It can serve as a starting point for power-based training targets, but it does not guarantee that you can sustain exactly 247 W for a fixed duration. Note: The common 95% factor is approximate and depends on test preparation and athlete.
Limitations
This calculation assumes the entered power represents a valid, well-paced maximal 20-minute test. Warm-up protocol, prior fatigue, cooling, motivation, altitude, and power-device accuracy can affect the result. The 0.95 factor does not account for individual differences in anaerobic contribution or endurance, so it may overestimate or underestimate FTP. The result is not a direct measurement of lactate threshold or a guarantee of one-hour sustainable power. Maximal testing is strenuous; seek appropriate medical guidance if you have symptoms or health concerns before attempting it.
Common questions
Why does the calculator multiply 20-minute power by 0.95?+
A rider can generally produce more power for 20 minutes than for a longer threshold effort. The common 0.95 factor reduces the test average to approximate FTP, but the appropriate reduction varies with the athlete and test preparation.
Should I enter normalized power or average power from my cycling computer?+
Enter average power for the exact 20-minute test interval. Normalized power weights fluctuations differently and is not the input used by this formula; including warm-up or cooldown time also changes the result.
Does an estimated FTP of 247 W mean I can ride at 247 W for exactly one hour?+
No. With the default inputs, 247 W is an estimate derived from 260 W multiplied by 0.95. Actual time to exhaustion at that power varies, so use subsequent training performance or a suitable follow-up assessment to check the estimate.
When should I change the protocol adjustment factor?+
Change it only when your specific testing protocol or an individualized assessment supports a different multiplier. Do not adjust it simply to reach a preferred FTP; keep test preparation and measurement conditions consistent when comparing results.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.