Log inStart free
← All calculators
Free cycling calculator

Cycling FTP & Power Zones Calculator

Turn a recent, well-paced effort into a usable training reference. This FTP zones and watts-per-kilogram calculator shows every formula, keeps the raw test result visible, and treats FTP as an estimate to validate in training—not a permanent label.

Private by design: calculations run in your browser. Nothing is uploaded or saved.

Your inputs

Calculate your working zones

Starting point
W
Use a maximal, evenly paced effort.
Estimated FTP285 W

3.80 W/kg

300 W × 0.95 = 285 W

Power training zones calculated from an FTP of 285 watts
ZonePowerPrimary use
Z1Active recovery≤ 156 WCirculation with minimal added stress
Z2Endurance157–213 WAerobic durability and economical steady riding
Z3Tempo214–256 WSustained aerobic work with moderate fatigue
Z4Threshold257–299 WSustained work around maximal steady intensity
Z5VO₂max300–342 WShort, severe-intensity aerobic intervals
Z6Anaerobic capacity343–427 WVery hard efforts lasting roughly 30 seconds to 3 minutes
Z7Neuromuscular power≥ 428 WShort maximal sprints; percentage targets are not prescriptive

Zone borders are guides, not physiological cliffs. Use breathing, RPE and repeatability beside power.

What this calculator does

Enter a known FTP or estimate it as 95% of a maximal 20-minute mean power. The seven displayed zones use the widely adopted percentage ranges popularized by Hunter Allen and Andrew Coggan. Boundaries are rounded to whole watts so they are usable outdoors and on a trainer.

The 95% correction is a convention, not a physiological law. Research finds the protocol can be repeatable, yet the relationship between 20-minute power, maximal lactate steady state and critical power varies between riders. Use the result as a starting point and adjust when repeatable workouts show it is clearly too high or too low.

How to perform a useful 20-minute test

Test when rested, on familiar equipment, with consistent cooling and calibration. Warm up progressively, include a few short efforts, then ride 20 minutes as evenly as possible. Starting too hard inflates fatigue and usually lowers the final average. Repeat under similar conditions when you want to compare results.

Do not retest after every strong ride. Day-to-day freshness, heat, altitude, terrain and indoor cooling can all move the number. A consistent protocol and a trend across several weeks are more informative than one personal best.

Methodology and sources

The formula and limitations above were checked against these research sources:

  1. Borszcz et al. (2020), Reliability of Functional Threshold PowerReliability and expected variation in a standardized 20-minute FTP protocol.
  2. Lillo-Beviá et al. (2022), FTP and maximal lactate steady stateEvidence that one correction factor does not perfectly estimate physiological threshold for every rider.
  3. Karsten et al. (2021), Critical Power and 20-minute FTPStrong relationship but meaningful individual disagreement between the two metrics.
Common questions

Before you use the result

Is FTP exactly 95% of 20-minute power?

No. Ninety-five percent is a practical population-level convention. Individual anaerobic contribution and fatigue resistance mean the best correction can differ between riders.

How do I calculate cycling watts per kilogram?

Divide FTP in watts by body weight in kilograms. For example, 250 W divided by 70 kg is 3.57 W/kg. The calculator shows this result automatically, but compare it carefully because equipment, testing conditions and body composition also matter.

How often should I test FTP?

Usually every 6–8 weeks is enough during consistent training, or after a clear phase change. Testing more often can confuse normal day-to-day variation with fitness change.

Can I use these zones without a power meter?

The watt ranges require power, but the intent of each zone can be followed with perceived effort and the talk test. FTP500 workouts include RPE guidance for this reason.

Build the knowledge around the number