This FTP calculator turns your functional threshold power into the full Coggan power-zone table for training — personalized in watts — and places your watts-per-kilogram on the rider-category ladder.

Retest every 4–8 weeks of training — zones are only as honest as the FTP beneath them. An overestimated FTP makes Zone 2 a lie and structured training a slow-motion bonk.

FTP: the Hour-Power That Organizes Training

Functional threshold power — the highest power you can sustain for roughly an hour — anchors every Coggan zone as a percentage band. It converts “ride hard” into prescribed watts. Gearing decides which cadence those watts arrive at (our Bike Gear Calculator); FTP decides what the legs must produce. Part of our Sports Calculators collection.

Worked Example (Verified)

  • FTP 250 W, 75 kg (defaults): 3.33 W/kg — solid Cat 3/4 borderland on the Coggan profile
  • Zones: endurance Zone 2 = 140–188 W; threshold work at 228–263 W; VO₂ intervals 265–300 W
  • From a 20-minute test: average 263 W × 0.95 ≈ 250 W FTP — the selector applies the standard 0.95 factor for you; ramp-test peaks convert at ≈ 0.75
  • W/kg is the climbing currency: on a 8% grade, the 3.33 W/kg rider and a 4.0 W/kg rider separate by minutes per climb regardless of identical raw FTP at different weights

Testing Honestly

  • Protocols: 20-minute test (× 0.95), 2 × 8-minute (× 0.90 of the better), ramp test (× ~0.75 of the final minute) — all estimate the same hour-power with different suffering profiles.
  • Indoor vs outdoor FTP routinely differ 5–15 W (cooling, position, motivation); keep zones protocol-specific.
  • A hero test after a taper inflates zones for a month of misery — test in a normal training week, fueled, and repeat the same protocol every time.

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Frequently Asked Questions

What is FTP in cycling?

Functional threshold power: the highest average power sustainable for about an hour, in watts. It anchors training zones (Coggan’s seven bands are all percentages of FTP) and, divided by weight, predicts climbing performance as W/kg.

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

Multiply your best 20-minute average power by 0.95 — the standard correction from 20 minutes to hour-power. 263 W × 0.95 ≈ 250 W. This calculator’s source selector applies the factor (and the ramp-test 0.75) automatically.

What is a good W/kg?

Context from Coggan’s profile: ~2.5 W/kg is a fit recreational rider, 3.3 a strong club racer (the worked example), 4.0 Cat 2 territory, ~5.0 domestic pro, and Grand Tour winners exceed 6.0 on climbs. Every 0.1 W/kg is months of training — the ladder is steep near the top.

What are the Coggan power zones?

Seven bands by %FTP: recovery <55%, endurance 56–75%, tempo 76–90%, threshold 91–105%, VO₂ max 106–120%, anaerobic 121–150%, neuromuscular above. The table prints yours in watts from your FTP.

FTP or heart rate zones — which should I train by?

Power leads (instant, weather-proof, drift-free) when you have a meter; heart rate lags efforts by 20–60 seconds and drifts with heat and fatigue, but costs nothing and works on any bike. Serious setups run both: watts prescribe, pulse sanity-checks.

Is this FTP calculator free?

Yes — free, instant, no sign-up.