What is FTP in cycling? A complete guide to Functional Threshold Power

Why FTP became the most argued-about number in cycling

Before Andrew Coggan and Hunter Allen published Training and Racing with a Power Meter in 2006, serious cyclists had two options for prescribing intensity: heart rate, which drifts with heat, caffeine, sleep and fatigue, or a lab lactate test that cost €200, took half a day, and had to be repeated every few months to stay honest. Coggan and Allen proposed a simple field surrogate: the highest average power a rider could hold for about an hour. Not a physiological measurement — a functional one.

The idea exploded because it was repeatable, cheap, and accurate enough. Every coaching platform built itself around it. Zwift uses it, TrainerRoad uses it, TrainingPeaks uses it, CoreRise uses it. The argument that still runs at 11pm on cycling forums isn't whether FTP matters — it's which test estimates it best, how often to retest, and whether the single hour-power number hides more than it reveals. This guide addresses all of that.

What does FTP mean? (Definition)

Functional Threshold Power is the highest average power, in watts, that a trained cyclist can sustain in a quasi-steady state for approximately one hour. The word that matters is functional: FTP is not your laboratory lactate threshold, it is not your VO2max power, and it is not your critical power in the strict mathematical sense. It is a field estimate of the boundary between an effort you can hold for a long time and one that starts tearing you down.

Above FTP, blood lactate accumulates faster than your body can clear it, muscular fatigue stacks up quickly, and the clock until failure shrinks with every extra watt. Below FTP, lactate is being produced and cleared at roughly the same rate, you can hold a conversation at the low end of the range, and an athlete in decent shape can ride for hours. FTP is the hinge between those two worlds.

Why does FTP matter so much?

FTP is the anchor of every modern training system because almost everything you care about is expressed as a percentage of it. Change the FTP, and every downstream number changes too.

• Training zones — endurance, tempo, sweet spot, threshold, VO2max, and anaerobic efforts are all defined as a percentage of FTP.
• Workout targets — a coach prescribing 4 × 8 min at 105% FTP is giving you a precise, repeatable dose.
• Training Stress Score (TSS) — the load of every ride is calculated relative to an hour spent at FTP. A one-hour ride at exactly FTP equals 100 TSS.
• Pacing — in a time trial, gran fondo, or Ironman bike leg, your target power is set as a fraction of FTP (often 85–95% for a 40k TT, 65–75% for a long-course triathlon).
• Progress tracking — if your FTP climbs from 240W to 265W over a block, the training is working. If it does not move, something needs to change.

How do you measure your FTP? (The three main tests)

You do not need a laboratory. Three field tests dominate, each with trade-offs. Pick the one that fits your training age, your equipment, and your honesty with pain. The cardinal rule is: do not mix protocols between retests. If you tested with a ramp last time, test with a ramp this time — the number is only useful as a trend.

The 20-minute FTP test

The most common protocol and the one Coggan and Allen originally popularized. After a proper warm-up (20–30 min easy, a few short openers, one or two 1-minute openers), you ride as hard as you can sustain for exactly 20 minutes. Your FTP is estimated as 95% of that 20-minute average power.

The 95% factor exists because 20 minutes is shorter than an hour, so your 20-minute average is higher than your true hour power. The test rewards athletes who can pace evenly and punishes those who blow up in the first five minutes. If your first two minutes are 10% above the rest, your result underestimates your real FTP.

Best for experienced cyclists who are comfortable pacing a hard, even effort. Allow a 5-minute max effort before the 20-minute test to suppress your anaerobic contribution — this is the Allen/Coggan protocol. Many athletes skip it and get inflated numbers.

The ramp test

Popularized by Zwift and now the default in most smart-trainer apps. You start at a low power target and the resistance increases by a fixed amount (typically 20W per minute for men, 15W for women) until you can no longer hold it. Your FTP is estimated as 75% of your best one-minute average power.

The advantage: it is short (20–25 minutes total), mentally easier than a 20-minute time trial, and works well for newer athletes who have not learned to pace a hard effort. The disadvantage: it tends to overestimate FTP for athletes with strong anaerobic capacity and underestimate it for diesel-engine endurance types who cannot hit a sharp one-minute power.

Best for athletes new to testing, or anyone who dreads the 20-minute protocol. Not ideal for riders whose race needs are 3+ hours of steady power.

The 8-minute test

Two maximal 8-minute efforts separated by 10 minutes of easy spinning. FTP is estimated as 90% of the average power across the two efforts. It is the shortest of the classic protocols but also the noisiest — your pacing has to be excellent and you have to genuinely empty the tank twice for the number to mean anything.

Best for time-crunched athletes who already know how to pace a hard effort.

Which FTP test should you choose?

The table below maps each protocol to the kind of rider it fits best. The honest answer for most athletes is: pick one and stick to it. The between-test variance from switching protocols is larger than the between-test variance from real fitness changes, which means a "ramp-then-20-min" comparison tells you nothing useful about whether your training is working.

How do you turn your FTP into training zones?

Once you know your FTP, the Coggan 7-zone model gives you a clear map of what each intensity does. These are the ranges every modern coaching platform — CoreRise, TrainingPeaks, TrainerRoad, Zwift — uses as a foundation. The example watts in the table are calculated for a rider with a 250W FTP; scale linearly to your own number.

The exact percentages matter less than the purpose of each zone. A watt or two either side of 75% does not turn an endurance ride into a tempo ride — stop stressing the boundaries.

What is a good FTP? (FTP chart by level and W/kg)

Raw watts are a bar-room stat. The number that actually determines how fast you go up a hill or hold position in a group is watts per kilogram (W/kg) — your FTP divided by your body mass. A 300W FTP at 90kg climbs like a 200W FTP at 60kg. The table below is adapted from the Coggan power profile and reflects roughly where cyclists sit at different levels.

These numbers are for sustained FTP, not for 5-second sprints or climbing PR hero-stats. Road-race categories also depend on durability (FTP after 3 hours, not fresh), which a single watts-per-kg number never shows.

How often should you retest your FTP?

Every four to six weeks of consistent training is the practical answer. Less often than that and your zones drift out of date; you end up training to an old version of yourself, and your Zone 2 slowly becomes your new tempo. More often than that and testing becomes a fitness-draining ritual with too much noise and not enough signal.

You do not always need a formal test, either. If your 2 × 20 min threshold intervals at what used to be 98% of FTP now feel like zone 3, your fitness has moved — you can bump FTP by 3–5% and retest properly when the block wraps up. Most good coaches use both: a proper retest at the end of each block, plus informal upward nudges mid-block when the signs are obvious.

How to improve your FTP

The single biggest mistake amateur cyclists make is trying to move FTP directly with more FTP-level intervals. The number that goes up fastest — for beginners and intermediates alike — goes up when you train the zones underneath and around it, not when you grind through endless 2 × 20s at threshold.

The honest version is that FTP improves through three distinct adaptations, each requiring a different kind of work. You build aerobic engine and fat oxidation with Zone 2 volume. You raise the ceiling FTP can approach with VO2max intervals. And you move the threshold itself with sweet spot and threshold blocks. Skipping any of the three plateaus your progress; doing all of them in sequence is what periodized training is for.

• Build an aerobic base first. 6–10 weeks of mostly Zone 2 rides before intensity. Boring, unavoidable, decisive.
• Add sweet spot (88–94% FTP) in 2 × 20 or 3 × 15 min blocks, twice a week in build weeks. This is where most amateur FTP gains come from.
• Layer VO2max intervals (e.g. Norwegian 4×4s, 5 × 5 min at 110–120% FTP) once the base is in. Raises the ceiling your FTP can grow toward.
• Recover. A threshold block without proper recovery weeks stalls. Every 3rd or 4th week should drop volume by 30–40%.
• Track it. Log every session, look at the trend, retest at the end of each block — do not stare at daily fluctuations.

A beginner can add 10–15% FTP in their first serious training block (8–12 weeks). An intermediate athlete might gain 3–7% per focused block. At the elite end, a single-digit percent over a season is a win. The curve flattens with training age — which is why long-course triathletes eventually focus on durability and race execution over chasing more raw FTP.

What are the common mistakes with FTP?

Three traps catch almost every cyclist who gets serious about power. None of them have to do with the test protocol or the zone math — they have to do with how the number is used.

• Chasing the number instead of the training. A rising FTP is a consequence of consistent, well-structured work — not a goal you can force by retesting every Sunday.
• Testing at the wrong time. Testing after a hard week, on broken sleep, or at the end of a heat wave gives you a number that reflects fatigue, not fitness. Retest rested.
• Ignoring durability. Two cyclists with the same FTP can finish a 5-hour ride in very different states. How much of your FTP you can hold after 3 hours — the "durability" metric — matters more than the fresh number for long-course triathletes and gran fondo riders. This is a newer concept in the research (Maunder, Seiler) but it is reshaping how good coaches think about threshold work for endurance events.

Does FTP exist for running and swimming?

Yes — the language changes, but the concept is the same. In running, the analogue is threshold pace, sometimes called functional threshold pace, or derived from a Critical Power model if you run with a power meter. In swimming, it is CSS (Critical Swim Speed), usually set from a 400m + 200m test. The workflow is identical: test, derive zones, train the zones, retest.

Modern coaching does not treat these as three separate worlds. A good multisport plan blends bike FTP, running threshold, and swim CSS into one coherent weekly load — which is the whole reason Training Stress Score was invented, and which is exactly how the CoreRise coach plans a triathlon week.