Functional Threshold Power Calculator

How it is calculated

The tool applies one multiplier: FTP = 0.95 × P20. P₂₀ is your average power in watts over a maximal, evenly paced 20-minute effort, as read from a power meter or smart trainer. The result is rounded to a whole watt. Power must be above zero, otherwise nothing is returned. The 95% factor is a standard shortcut that assumes the 20-minute effort overstates what you could hold for an hour; it does not adjust for rider type, so strong sprinters and endurance specialists can differ. The tool gives FTP only; it does not compute training zones or W/kg, which you get by dividing FTP by body weight in kilograms.

Common mistakes

• Using the average of the whole ride instead of the 20-minute test segment. Warm-up and recovery watts pull the number far below your real FTP.
• Starting the test too hard and fading. An even effort gives a true average; a blown start leaves you with an underestimated 20-minute number.
• Entering normalized power or the best peak 5-minute power. The field expects the plain average power over 20 minutes.
• Applying the 95% twice, for instance by typing a value you already multiplied by 0.95. The tool does that step itself.
• Testing on a different bike or trainer from the one you train on, so the numbers do not match your usual power meter.