Inflection Cycling FTP Calculator

Browser ready No spreadsheet or PDF application is required. Select the assessment method and the power zones update immediately.

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Athlete name

Date

Assessment method

20-minute average power (W)

Enter an average power from 50 to 2,000 W.

Functional threshold power -- W

Calculation basis --

Cycling power zones

ZoneIntensityPower range

1Active recovery≤55% FTP --

2Endurance56–75% FTP --

3Tempo76–90% FTP --

4Lactate threshold91–105% FTP --

5VO₂max106–120% FTP --

6Anaerobic capacity121–150% FTP --

7Neuromuscular power>150% FTP --

How to use it

Select the assessment method used to establish FTP.
Enter either 20-minute average power or an established FTP.
Use the calculated watt ranges with the prescribed session intent.

Calculation method

For the 20-minute method, FTP is estimated as 95% of average power. Direct entry preserves an FTP established through another assessment. Zone boundaries are calculated from the resulting FTP and rounded to whole watts.

Use with context

FTP is a practical training estimate rather than a fixed physiological constant. Protocol, equipment, calibration, environment, fatigue, and pacing may influence the result. Reassess under comparable conditions and interpret power alongside perceived exertion and coach guidance.