endurance Formula

Cycling FTP Power Zones Formula

Cycling power zones are percentages of Functional Threshold Power (FTP) — the maximum sustainable power over ~1 hour. Coggan's 7-zone system maps zone boundaries as percentages of FTP. FTP itself is estimated from a 20-minute all-out time trial, with a 5% correction (20-min test produces ~5% higher power than true 1-hour pace). All training prescriptions are read off these zones.

4 VARIABLESPublished May 14, 2026Live Content

By AI Fit Hub · AI Fit Hub Team

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Cycling Power & FTP Zone Calculator

Calculate your 7 Coggan power training zones from FTP or a 20-minute test result with W/kg ratio.

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Formula 4 variables Worked example Variations

Education · Not medical advice. Output is deterministic math from your inputs.Editorial standards Sponsor disclosure Corrections

Formula

Copy the exact expression or work through it step by step below.

 FTP_estimate ≈ 20-min average power × 0.95
   Zone 1 (Active Recovery):     ≤ 55% FTP
   Zone 2 (Endurance):         56-75% FTP
   Zone 3 (Tempo):             76-90% FTP
   Zone 4 (Threshold):         91-105% FTP
   Zone 5 (VO2 max):          106-120% FTP
   Zone 6 (Anaerobic Cap.):   121-150% FTP
   Zone 7 (Neuromuscular):       > 150% FTP

Variables

FTP

Functional Threshold Power

Maximum power (in watts) sustainable for approximately one hour. Anchors all training zones. Re-test quarterly during build phases; expect 3-8% per training block in untrained-to-intermediate cyclists.

20-min_average_power

20-minute test power

Average watts during a maximal 20-minute time trial. Use a power meter (pedal-based, crank-based, or smart trainer). Warm up properly: 20 min easy + 3×1 min hard with 1 min recovery before the 20-min effort.

correction_factor

0.95 multiplier

Coggan's empirical adjustment: 20-min test power is ~5% higher than true 1-hour sustainable power because the 1-hour-vs-20-min metabolic drift adds up. Allen & Coggan 'Training and Racing with a Power Meter' (2010).

zone_boundary_pct

Zone boundary percentages

Fixed percentages of FTP. Standard 7-zone Coggan model. Some coaches use 5- or 6-zone variants; the boundary numbers usually still align with these percentages.

Step By Step

1

Schedule the 20-minute FTP test on a rested day. Warm up 20 min easy + 3×1 min at 110% perceived FTP with 1 min spin recovery between.

Sunday 10:00 — warmup 20 min, primer intervals, 5 min easy, then start 20-min effort at sustainable max.
2

Pace the 20 min: first 5 min slightly above target, middle 10 min steady, last 5 min hold or push. Record average watts at end.

Result: 290 W average for 20 min.
3

Apply correction: FTP = 0.95 × 20-min power.

FTP = 0.95 × 290 = 275.5 → 275 W.
4

Compute zone bands as percentages of FTP.

Z1 ≤151, Z2 154-206, Z3 209-247, Z4 250-289, Z5 292-330, Z6 333-413, Z7 >413. (Calculated from 275 × percentage bounds.)
5

Use zones for training prescription. Z2 = base aerobic (long rides 2-4h). Z4 = threshold intervals (e.g., 4×10 min @ Z4). Z5 = VO2 max intervals (e.g., 6×4 min @ Z5).

Tuesday: 4×10 min @ 280 W (Z4 mid). Saturday: 4h endurance @ 180 W (Z2).

Worked Example

Intermediate cyclist (75 kg) doing first FTP test of the season

20-min test result

290 W average

Body weight

75 kg

FTP = 0.95 × 290 = 275 W W/kg = 275 / 75 = 3.67 W/kg (Cat 4-5 amateur range) Zone bands (in watts): Z1 ≤151, Z2 154-206, Z3 209-247, Z4 250-289, Z5 292-330, Z6 333-413, Z7 >413

FTP 275 W (3.67 W/kg). Coggan power-profile categorization: untrained 1.5-2.5 W/kg, recreational 2.5-3.5, cat 3-4 amateur 3.5-4.5, cat 1-2 amateur 4.5-5.5, pro 5.5-6.5+. Training prescription: 3 weekly sessions — Z2 long ride (3h), Z4 threshold (4×10 min), Z5 VO2 (5×4 min) with Z2 between intervals.

Common Variations

Ramp test (8-min step protocol): start at 100 W, increase 20 W every minute until failure. Multiply final completed minute's power by 0.75 for FTP. Faster than 20-min test, less precise (~3% error).

60-min all-out test: the 'true' FTP measurement. Rarely used because mentally brutal. 20-min × 0.95 is the practical proxy.

Critical Power model (Skiba 2007): more recent academic framework that replaces FTP with CP (Critical Power) and W' (anaerobic work capacity). More accurate at the extremes; FTP still works for typical training zones.

Power-to-weight (W/kg): for climbing-heavy races, W/kg matters more than absolute W. Pro climbers hit 6+ W/kg at threshold; pro time trialists 6-7 W/kg in 1-hour efforts.

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FAQ

Questions people ask next

The short answers readers usually want after the first pass.

How do I calculate cycling power zones from FTP?

Cycling power zones are fixed percentages of your Functional Threshold Power (FTP). The Coggan 7-zone system runs: Zone 1 Active Recovery at 55% or below FTP, Zone 2 Endurance 56-75%, Zone 3 Tempo 76-90%, Zone 4 Threshold 91-105%, Zone 5 VO2 max 106-120%, Zone 6 Anaerobic Capacity 121-150%, and Zone 7 Neuromuscular above 150%. Multiply your FTP in watts by each percentage to get the watt band for each zone.

What are the British Cycling / Coggan power zones?

The standard model on this page is Coggan's 7-zone system, anchored to FTP. Some coaches use 5- or 6-zone variants (a British Cycling style grouping is one such variant), but the boundary numbers usually still align with these same FTP percentages. The seven zones are Active Recovery, Endurance, Tempo, Threshold, VO2 max, Anaerobic Capacity, and Neuromuscular.

How do I estimate FTP from a 20-minute test?

Do a maximal 20-minute time trial after a proper warm-up (about 20 min easy plus 3x1 min hard with 1 min recovery), then multiply your 20-minute average power by 0.95. The 5% reduction is Coggan's empirical correction because a 20-minute effort produces roughly 5% higher power than your true one-hour sustainable pace. Example: a 290 W 20-minute average gives an FTP of 0.95 x 290 = 275 W.

Why multiply the 20-minute test by 0.95 instead of using the full number?

Because a 20-minute all-out effort is not the same as a true one-hour effort. FTP is defined as the maximum power sustainable for about one hour, and metabolic drift means 20-minute power runs about 5% higher than one-hour power. The 0.95 multiplier (Allen & Coggan, Training and Racing with a Power Meter) corrects the shorter test down to a realistic one-hour threshold.

Is there a faster alternative to the 20-minute FTP test?

Yes, the ramp test (8-minute step protocol): start near 100 W and increase 20 W every minute until failure, then multiply the final completed minute's power by 0.75 to estimate FTP. It is faster than the 20-minute test but less precise, with roughly 3% error. The true reference is a 60-minute all-out test, which most riders skip because it is mentally brutal.

Sources & References

Allen & Coggan (2010). Training and Racing with a Power Meter (2nd ed.). — VeloPress — foundational power-training textbook
Coggan & Allen (2003). Training and racing using a power meter: an introduction. — ResearchGate (Coggan archives) — original zone system
Skiba & Jones (2007). The critical power concept: a useful tool for the endurance athlete. — Sportscience — Critical Power framework
Pinot & Grappe (2011). The record power profile to assess performance in elite cyclists. — International Journal of Sports Medicine — W/kg performance categories