Functional Threshold Power is the highest average wattage you can sustain for approximately 60 minutes. It is the most widely used reference point in cycling training because it scales all 7 zones proportionally.

Why multiply 20-min power by 0.95?

Most cyclists can sustain roughly 95% of their 20-minute best effort for a full hour. This 5% reduction is the standard Coggan correction. Some riders use 90–92% if they tend to go out too hard; experienced pacers can use 96–97%.

Recreational: 2–3 W/kg. Trained club rider: 3–4 W/kg. Competitive amateur: 4–5 W/kg. Cat 3 racer: ~4.5 W/kg. Elite amateur: 5–6 W/kg. Professional: 6–7 W/kg. These are for sustained efforts, not short sprints.

How often should I retest FTP?

Every 6–8 weeks during a structured training block. If you've been riding consistently for 3+ months, you may see 10–15% FTP gains and your zones will shift significantly enough to warrant an update.

Yes. All calculations are client-side. No data leaves your browser.

Methodology: Cycling Power & FTP Zone Calculator

Scope

Computes the seven Coggan power training zones from FTP or from a 20-minute test result.

Formula

FTP = 0.95 * power_20min. Zone_n_range = coggan_pct_range_n * FTP.

Coefficients

Parameter	Value	Note
Z1 Active Recovery	`< 55% FTP`
Z2 Endurance	`56–75% FTP`
Z3 Tempo	`76–90% FTP`
Z4 Lactate Threshold	`91–105% FTP`
Z5 VO2 Max	`106–120% FTP`
Z6 Anaerobic	`121–150% FTP`
Z7 Neuromuscular	`> 150% FTP`

Data sources

Allen H, Coggan A, McGregor S. Training and Racing with a Power Meter. 3rd ed. VeloPress, 2019. — Publisher page; source of the seven-zone Coggan model.
Coggan A. Power training zones for cycling. TrainingPeaks (author reference). — Coggan's canonical public reference for the zone definitions.
Borszcz FK, Tramontin AF, Bossi AH, Carminatti LJ, Costa VP. Functional threshold power in cyclists: validity of the concept and physiological responses. Int J Sports Med. 2018;39(10):737-742. — PMID 29801179. Validation study on the 20-min x 0.95 FTP protocol.

Assumptions

Power meter is calibrated; 20-min test effort was honest.

Approximation range

FTP from 20-minute x 0.95 slightly over-estimates true FTP for well-trained cyclists; under-estimates for sprinters.

Limitations

Zones drift as fitness changes — re-test FTP every 6–8 weeks.
Indoor FTP can be 5–10% lower than outdoor FTP for the same rider.

Reproducibility

20-min power 300 W. FTP = 285 W. Z2: 0.56*285–0.75*285 = 160–214 W.

Change log

2026-04-24: methodology page first published.

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Worked example

Computed by the same engine bundle served at /engines/cycling-power-ftp-zone-calculator.js. Re-runnable: the values below are the literal output of compute(engineInput).

Input

tool: cycling_power_ftp_zone_calculator
ftp: 250
weight_kg: 75

Output

ftp: 250
wPerKg: 3.333333
wPerKgCategory: Trained
zones: [{"zone":1,"name":"Active Recovery","description":"Very easy, recovery rides. <55% FTP.","minWatts":0,"maxWatts":138},{"zone":2,"name":"Endurance","description":"All-day aerobic base. 56–75% FTP.","minWatts":140,"maxWatts":188},{"zone":3,"name":"Tempo","description":"Sustained effort, comfortably hard. 76–90% FTP.","minWatts":190,"maxWatts":225},{"zone":4,"name":"Lactate Threshold","description":"Race pace, 1-hour max effort. 91–105% FTP.","minWatts":228,"maxWatts":263},{"zone":5,"name":"VO2 Max","description":"Hard interval work, 3–8 min. 106–120% FTP.","minWatts":265,"maxWatts":300},{"zone":6,"name":"Anaerobic Capacity","description":"Short maximal efforts, 30s–2 min. 121–150% FTP.","minWatts":303,"maxWatts":375},{"zone":7,"name":"Neuromuscular","description":"Sprint power, <30 sec. >150% FTP.","minWatts":378,"maxWatts":null}]

FAQ

What is FTP?: Functional Threshold Power is the highest average wattage you can sustain for approximately 60 minutes. It is the most widely used reference point in cycling training because it scales all 7 zones proportionally.
Why multiply 20-min power by 0.95?: Most cyclists can sustain roughly 95% of their 20-minute best effort for a full hour. This 5% reduction is the standard Coggan correction. Some riders use 90–92% if they tend to go out too hard; experienced pacers can use 96–97%.
What is a good W/kg?: Recreational: 2–3 W/kg. Trained club rider: 3–4 W/kg. Competitive amateur: 4–5 W/kg. Cat 3 racer: ~4.5 W/kg. Elite amateur: 5–6 W/kg. Professional: 6–7 W/kg. These are for sustained efforts, not short sprints.
How often should I retest FTP?: Every 6–8 weeks during a structured training block. If you've been riding consistently for 3+ months, you may see 10–15% FTP gains and your zones will shift significantly enough to warrant an update.
Is this tool free?: Yes. All calculations are client-side. No data leaves your browser.