Turn a 20-minute, 8-minute or ramp test into an estimate of your Functional Threshold Power, with the training zones that come with it.
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Training zones (Coggan 7-zone model)
| Zone | % FTP | Watts |
|---|---|---|
| Z1 · Active Recovery | 0–55% | 0–146 W |
| Z2 · Endurance | 56–75% | 149–200 W |
| Z3 · Tempo | 76–90% | 202–239 W |
| Z4 · Lactate Threshold | 91–105% | 242–279 W |
| Z5 · VO2max | 106–120% | 282–319 W |
| Z6 · Anaerobic Capacity | 121–150% | 322–399 W |
| Z7 · Neuromuscular Power | 151+% | 402+ W |
FTP estimated from a field test is a modeling convention, not a lab measurement. An indoor ramp test, an outdoor 20-minute effort and a formal lab test can each give a slightly different number for the same rider.
A true one-hour maximum is hard to pace and draining to repeat, so riders use shorter tests and apply a protocol-specific multiplier. These multipliers are estimation conventions, not physiological constants:
| Protocol | Multiplier | What you ride | Good to know |
|---|---|---|---|
| 20-minute test | × 0.95 | One all-out 20-minute effort after a thorough warm-up | The most common field test. Needs good pacing; starting too hard is the usual mistake. |
| 8-minute test | × 0.9 | An all-out 8-minute effort (often done twice with full recovery; enter your best average) | Shorter on the clock, but the multiplier is steeper than the 20-minute test, so small pacing errors matter more. |
| Ramp test | × 0.75 | Power rises in steps until you can no longer continue; you use your best one-minute power | No pacing decisions, which suits smart trainers. Its multiplier depends on the specific ramp protocol. |
Whichever you choose, stick with it between retests. Switching protocols changes the number for reasons that have nothing to do with fitness.
Some coaches add an all-out five-minute effort before the 20 minutes to load the legs. The 0.95 multiplier used here corresponds to the plain 20-minute test.
The chart shows what the calculator returns for common results, so you can sanity-check the arithmetic:
| 20-minute average | FTP | Best 1-minute ramp power | FTP |
|---|---|---|---|
| 200 W | 190 W | 300 W | 225 W |
| 240 W | 228 W | 350 W | 263 W |
| 280 W | 266 W | 400 W | 300 W |
| 320 W | 304 W | 450 W | 338 W |
A rider who averages 265 W for 20 minutes has an estimated FTP of 252 W, which is 3.6 W/kg at 70 kg.
Absolute watts say little on their own, because FTP depends heavily on body size. For a 75 kg man, the "Moderate", "Good", "Excellent" and "World Class" rows of the Coggan power profile chart work out to about 247, 287, 374 and 453 W. The chart was built for young adult racers, so older and recreational riders often sit lower. Power divided by weight is the fairer yardstick, and the W/kg calculator shows where your ratio falls on the Coggan power-profile scale, with a chart that converts FTP to W/kg for common weights. Power-to-weight is also what sets climbing pace, which the hill climb calculator turns into a finish time.
Not reliably. Outdoor speed reflects gradient, wind, drag, rolling resistance and drivetrain losses together, so the same speed can correspond to very different power on different days. Heart rate is no substitute, because it responds slowly and drifts with heat, fatigue and fitness. A power meter or smart trainer is the dependable way to test. Without one, the most you can do is estimate the power a known ride should have required. On the homepage you can calculate the watts for a planned ride from its speed and gradient, which is a rough planning figure, not a test result.
Three other calculators on this site build on your FTP. The power zones calculator turns it into seven Coggan training zones, each with a purpose and a watt range. The critical power calculator gives a related anchor from two maximal efforts plus W′, and will not match FTP exactly, which is expected. After each ride, the TSS calculator uses your FTP to score the training stress you added.
FTP is a modeling convention, not a fixed constant. It moves with fitness, fatigue, pacing skill and even indoor versus outdoor conditions, and the same rider can get slightly different values from different protocols in the same week. Retest every six to eight weeks during structured training, or after a clear jump in fitness, using the same protocol each time. A change in your number over time is more informative than any single reading.
