Estimate your Functional Threshold Power (FTP) from a 20-minute, 8-minute or ramp test, and see the training zones that follow from it.
| 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.
Functional Threshold Power is an estimate of the highest power a rider can sustain in a quasi-steady state without rapidly fatiguing. It's often associated with roughly one-hour performance, but the duration a given rider can actually sustain their FTP varies. It's the reference point most structured cycling training plans use to prescribe intensity — every training zone below is defined as a percentage of FTP, which is why it matters more than any single ride's power number.
FTP was historically associated with hour-scale threshold performance, but a full one-hour maximal effort is hard to pace and mentally taxing to repeat often — so most riders estimate FTP using shorter, more repeatable field or ramp-testing protocols instead. Each protocol applies its own multiplier, a protocol-specific estimation convention rather than a physiological law:
The 8-minute (×0.90) and ramp-test (×0.75 of peak 1-minute power) variants follow the same idea with different, shorter efforts — each multiplier is a selected estimation convention, not a universal constant.
20-minute test: a single sustained, all-out effort — the most widely used protocol, and the easiest one to pace consistently outdoors or indoors.
8-minute test: two shorter maximal efforts with recovery between them — quicker to complete, but relies on holding consistent pacing across two separate hard efforts.
Ramp test: power increases step by step until failure, so it needs no pacing strategy at all — popular on smart trainers — but its multiplier depends on the specific ramp protocol used, and it can estimate FTP somewhat differently than a sustained-effort test for the same rider.
None of the three is universally "more correct" — pick the one you can execute most consistently, and stay with the same protocol between retests so your trend over time is comparable.
Take a 165 lb rider who averages 280 W for a 20-minute all-out effort:
That's 3.55 W/kg for this rider — enter your own test result above to see your estimated FTP and the training zones that follow from it.
Dividing your FTP by body weight gives your threshold power-to-weight ratio — the number most often used to compare climbing potential across riders of different sizes. This calculator shows it alongside your FTP estimate; see the W/kg Calculator for the full power-to-weight reference table.
Andrew Coggan's widely-used 7-zone model scales every training intensity — from active recovery to neuromuscular power — as a percentage of FTP. The table above gives a quick zone preview from your estimated FTP; for the full breakdown with training purpose for every zone, see the Power Zones Calculator.
FTP and Critical Power (CP) are related but distinct: FTP is typically estimated from a single field test with a fixed multiplier, while CP is fit from two or more maximal efforts of different durations using a documented mathematical model, and comes with W′ (anaerobic work capacity) as an additional output FTP doesn't provide. Don't expect the two numbers to match exactly for the same rider — see the Critical Power Calculator to estimate yours.
Not reliably from speed alone. Outdoor speed is affected by gradient, wind, aerodynamic drag, rolling resistance and drivetrain losses, so the same power can produce very different speeds on different days or routes — speed by itself doesn't reliably determine power, let alone FTP. Heart rate is a different signal from power entirely — it responds slowly and drifts with heat, fatigue and fitness, so it isn't used here to derive FTP either. A power meter or smart trainer reporting real power output is the reliable way to test FTP.
FTP is a modeling convention, not a fixed physiological constant — it changes with fitness, fatigue, pacing ability, and even indoor-vs-outdoor testing conditions. Two riders with identical underlying fitness can produce different 20-minute-test estimates simply based on how well they pace a hard effort, and the same rider can get a slightly different number from a 20-minute test, an 8-minute test and a ramp test performed in the same week — each protocol's multiplier is a separate estimation convention, not measurements of the exact same underlying quantity. This is also why FTP estimates can differ between training platforms and devices — see the FAQ below.
