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 Orbyd Editorial · 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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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 (2014). The 'Power Profile' for the assessment of fitness in professional road cyclists. — Journal of Sports Sciences — W/kg performance categories