Last updated: 2026-06-29

Cycling FTP

Functional Threshold Power (FTP) is the highest average power output a cyclist can sustain for approximately one hour. It serves as the cornerstone of structured training with a power meter, because every training zone is defined as a percentage of FTP. This calculator estimates FTP from four common field-test protocols and converts the result into Coggan's seven power training zones.

What FTP measures

FTP approximates the lactate threshold — the exercise intensity above which lactate accumulates in the blood faster than the body can clear it. Riding at FTP intensity taxes both the aerobic and anaerobic energy systems near their combined capacity. Sustained efforts above FTP are limited by lactate accumulation; sustained efforts below FTP can be maintained for hours.

A rider with a higher FTP in absolute watts produces more power at threshold. A higher power-to-weight ratio (W/kg) indicates better climbing ability, because gravity imposes a constant weight penalty on every ascent.

Test protocols

20-minute test

The most widely used FTP test requires riding as hard as possible for 20 consecutive minutes after a standard warm-up. Because 20 minutes is shorter than one hour, most riders naturally produce about 5% more power than they could sustain for a full hour. Multiplying the 20-minute average by 0.95 corrects for this effect:

This protocol was established by exercise physiologist Andrew Coggan and coach Hunter Allen in their research on power-based training.

8-minute test

Two 8-minute all-out efforts (separated by 10 minutes of recovery) produce a slightly higher average power than a 20-minute effort because the shorter duration shifts more reliance to the anaerobic system. Multiplying by 0.90 accounts for this:

The 8-minute test is useful when 20-minute all-out efforts are impractical or when progressive fatigue from earlier training makes a longer test unreliable.

1-hour test

Riding at maximum sustainable effort for exactly one hour produces FTP directly — no correction factor is needed:

Because the test and the definition coincide, the 1-hour test is the most accurate protocol. In practice, many riders find an hour of maximal effort psychologically demanding and use the 20-minute test as a more manageable substitute.

Ramp test

The ramp test increases power in fixed steps — typically 20 W per minute — until the rider reaches exhaustion. Research shows that 75% of the average power during the final completed minute estimates FTP with reasonable accuracy:

The ramp test is shorter, requires less pacing judgment, and involves less pre-test anxiety, making it suitable for regular retesting.

Coggan power zones

Coggan's seven-zone system divides the effort spectrum into bands defined as percentages of FTP:

Each zone targets a distinct physiological adaptation. Zone 2 builds aerobic base with low fatigue cost. Zone 4 — riding at or near FTP — develops lactate threshold directly. Zones 5 and 6 raise VO₂ max and anaerobic capacity but accumulate fatigue rapidly and require careful scheduling.

Worked example

A rider completes a 20-minute test with an average power of 283 W and weighs 68 kg:

Zone 2 lower bound: $269 \times 0.55 = 148$ W. Zone 4 range: $269 \times 0.90 = 242$ W to $269 \times 1.04 = 280$ W.

A power-to-weight ratio of 3.96 W/kg places this rider at the upper end of the trained recreational category and within reach of competitive amateur performance.

Choosing and timing retests

FTP improves with training, so zones calculated from an outdated FTP become progressively too easy and provide less training stimulus over time. Retesting every 6–8 weeks during a structured block keeps zones accurate. Testing after a period of illness, travel, or significant accumulated fatigue will underestimate current ability; a short recovery block before testing produces more representative results.

The choice of protocol matters less than consistency — comparing FTP values over time is only meaningful when the same test protocol is used each time.