Choose the FTP method that matches your data
Functional threshold power, or FTP, is a practical reference for sustained cycling power and relative training intensity. Andrew Coggan's FTP explanation discusses ways of estimating it from field data. An FTP number is useful only when its origin is clear.
Use Known FTP if you already have an appropriate measured or previously estimated FTP. The calculator keeps that value and builds the zone table around it. Choose 20-minute estimate if your input is the average power for a hard 20-minute field-test effort. The tool applies the conventional 95% factor; it does not measure a physiological threshold.
Body mass is optional. Leaving it blank still produces the FTP and zone table. Enter kilograms or pounds only if you also want FTP expressed as rider-mass W/kg. The default 250 W is a labeled example, so replace it with your own data before treating the result as personal.
The 20-minute formula
Estimated FTP = 20-minute average power × 0.95.
Hunter Allen's explanation of power data describes this conventional shortcut. It is a starting estimate, not a universal conversion between every short effort and sustainable power. The calculator accepts the average for the test interval, not the highest instantaneous reading or the average of a warm-up and test combined.
For a 250 W 20-minute average, the estimate is 237.5 W, displayed as about 238 W. The zones still use 237.5 W internally. For a second example, 300 W × 0.95 gives 285 W. Neither calculation verifies how long that individual can actually sustain the estimated result.
How the seven-zone table works
This page uses a Coggan-style reference with a stated boundary convention, rather than claiming every presentation of power zones is identical. Coggan's original seven-level explanation treats physiological responses as a continuum and neuromuscular efforts as maximal rather than a fixed FTP prescription.
Our numeric bands use the cutoffs below. The upper boundary belongs to the lower zone; the next zone begins above it. Whole-watt rows end at the floor of each exact cutoff and begin one watt higher. This prevents gaps and overlaps in the displayed integers.
| Zone | Name | Exact convention used here |
|---|---|---|
| Z1 | Active recovery | 0 to 55% FTP, inclusive |
| Z2 | Endurance | Above 55% to 75%, inclusive |
| Z3 | Tempo | Above 75% to 90%, inclusive |
| Z4 | Threshold | Above 90% to 105%, inclusive |
| Z5 | VO2 max | Above 105% to 120%, inclusive |
| Z6 | Anaerobic capacity | Above 120% to 150%, inclusive |
| Z7 | Neuromuscular power reference | Above 150%; an effort-driven reference |
At a known FTP of 250 W, 55% is 137.5 W and 75% is 187.5 W. Z2 therefore means above 137.5 through 187.5 W, displayed as 138–187 whole watts. You may see rounded descriptions such as 56–75% or approximately 140–188 W elsewhere. Our display classifies the integer watts themselves, rather than independently rounding both endpoints.
The 150% split supplies a consistent numerical reference between the last two rows. It does not turn sprinting into an exact target range, and is not a claim that Coggan's original neuromuscular level has a fixed percentage ceiling or floor.
Getting a usable test input
Use a deliberate test protocol from a reliable training source and keep the protocol name with the recording. Plan an uninterrupted setting where traffic, junctions and descents do not interfere with the effort. Prepare your equipment according to its manufacturer's instructions, and identify the exact 20-minute interval in the completed file.
A field test is demanding. Choose an appropriate setting and effort for your experience and circumstances; this page is not a prescribed testing session. If you need a testing or training plan, use qualified coaching guidance rather than treating the Calculate button as permission to attempt a maximal effort.
The warm-up, pacing and preparation belong to the chosen protocol. Randomly selecting a fast 20-minute section of a group ride may not give the same estimate as a controlled field test. Do not substitute an eight-minute or ramp-test number into the 20-minute field: those are different methods.
What the estimate and zones leave out
Kolie Moore's discussion of FTP physiology and testing explains why short-test estimates and the duration of sustainable threshold efforts vary between riders. The 95% calculation can overestimate or underestimate an individual's useful FTP. Treat the output as a reference to evaluate alongside longer efforts and training observations.
Indoor and outdoor recordings also need context. Devices, cooling, position and test conditions may differ, so record the setting rather than assuming two numbers are directly interchangeable. A zone table organizes intensity; it does not specify interval duration, recovery, weekly load or what session is appropriate today.
For rider-mass interpretation, use the W/kg calculator. For travel planning, use the speed and time calculator with an actual or chosen average speed. FTP alone is insufficient to predict road speed.
Frequently asked questions
Should I enter normalized power?
For the 20-minute method here, enter average power over the selected test interval. A different derived power metric should not be substituted without a protocol that explicitly calls for it.
How often should I reassess FTP?
There is no schedule built into this tool. Reassessment should serve a useful question, such as whether the existing reference still fits sustained efforts after a training block or change in conditions. Record comparable methods rather than chasing small fluctuations from frequent tests.
Why can zones differ between platforms?
Platforms may choose different percentage bands, boundary ownership and rounding. Compare the definitions before concluding that the same FTP created an arithmetic error. This page states its exact conventions beside the results.
Is the calculated FTP a medical measurement?
No. It is either the number you entered or an arithmetic estimate. The zones are approximate references and do not establish a diagnosis or an individualized training prescription.
Method and sources
The method combines the conventional 20-minute estimate, Coggan's zone framework and the explicit boundary rules above. Read the FTP testing limitations alongside the formula. The cycling tools hub keeps these training references separate from route and gearing calculations.