Calculate your seven cycling power zones from FTP, or estimate FTP from a 20-minute test, and see which zone any wattage falls in.
How the Cycling Power Zones Calculator Works
Power zones turn one threshold value into repeatable workout targets. This calculator retains a simplified seven-band convention and identifies the band containing a specific wattage.
FTP is the anchor. The calculator applies continuous transitions at 55%, 75%, 90%, 105%, 120%, and 150% so every decimal watt has exactly one classification.
Formula and Method
Formula: zone boundary watts = FTP x boundary percentage; effort percentage = power / FTP x 100
Published Friel and Coggan tables use different endpoint conventions. This calculator uses lower-inclusive bands at the listed cut points; each upper endpoint belongs to the next band. This is an explicit calculator convention, not a universal definition.
Choosing the Right Inputs
Use a current FTP derived from a consistent test or training platform. In classification mode, enter average or target watts from the same power-meter basis as the FTP.
| Zone | Continuous band | Typical emphasis |
|---|---|---|
| Zone 1 | Below 55% | Active recovery |
| Zone 2 | 55% to below 75% | Aerobic endurance |
| Zone 3 | 75% to below 90% | Tempo |
| Zone 4 | 90% to below 105% | Threshold |
| Zone 5 | 105% to below 120% | VO2 max |
| Zone 6 | 120% to below 150% | Anaerobic capacity |
| Zone 7 | 150% and above | High-power / sprint convention |
Understanding Your Results
The FTP or classified zone leads. The supporting table shows watt targets for every band and, in classification mode, the exact percentage of FTP.
Zones are workout anchors rather than physiological walls. Short power spikes can sit well above FTP, while long intervals normally require progressively lower relative power.
Worked Example
With FTP set to 250 W, a 200 W effort is 80.0% of FTP and falls in Zone 3. A 310 W effort is 124.0% and falls in Zone 6.
Common Mistakes
Do not combine an indoor FTP with systematically different outdoor power without accounting for the difference, confuse heart-rate zones with power zones, or treat a one-watt boundary as a biological step change.
Assumptions and Limitations
Zone systems and device rounding vary. The 150% division is a convention retained by this calculator; Coggan’s original neuromuscular level has no fixed FTP percentage. These bands do not prescribe safe training. FTP can change with testing protocol, fatigue, environment and calibration.
Sources
TrainingPeaks: Joe Friel’s Quick Guide to Setting Zones; Andrew Coggan: Cycling Power Zones Explained.
