There is no single good number — it depends on your weight and goals. Watts per kilogram matters more: around 3 to 4 W/kg at threshold is a strong recreational level.

Do I need a power meter to know my FTP?

To measure FTP directly, yes — you need a power meter or a smart trainer that reports watts. Heart-rate-only estimates are rough because heart rate lags and drifts during hard efforts.

How often should I retest FTP?

Every four to six weeks during a training block. Testing too often gives noisy numbers; testing too rarely leaves your zones out of date as you get fitter.

Is the 20-minute test really an hour of power?

Taking 95 percent of a 20-minute effort approximates the power most riders could hold for an hour. It is an estimate, not a law — some riders hold closer to 90 or 100 percent depending on their physiology.

What Is Cycling FTP (Functional Threshold Power)?

Published 4/23/2026 · 3 min read · Sport calculators

Aisha Karim — Fitness & running writer at OneKitly

Running · Training

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In short

Functional Threshold Power (FTP) is the highest average power, measured in watts, that a cyclist can sustain for roughly one hour. It marks the boundary between efforts you can hold for a long time and efforts that quickly cause fatigue. FTP is the anchor for setting training zones, and dividing it by your body weight gives watts per kilogram — the number that best predicts climbing and racing performance.

A cyclist in gloves checking the watch on their wrist. — Atlantic Ambience · Pexels · Pexels

FTP is the highest power in watts you can hold for about an hour. Learn how to test it, why watts per kilogram matters, and how it guides training zones.

What FTP measures

FTP marks your lactate threshold in power terms: below it, your body clears lactate about as fast as it produces it, so you can ride a long time; above it, lactate builds and fatigue arrives quickly. It is the single most useful number for pacing hard efforts.

Because it is measured in watts, FTP is objective — unlike heart rate, it is not swayed by heat, caffeine, or sleep. Two riders with the same FTP are producing the same mechanical power at threshold.

How to test your FTP

The classic test is a 20-minute all-out effort on a power meter or smart trainer. Warm up thoroughly, ride as hard as you can hold for 20 minutes, then take 95 percent of your average power as your FTP estimate.

Shorter protocols exist, such as a ramp test that raises power in steps until you fail, and many apps estimate FTP automatically. Retest every four to six weeks to track progress and update your zones.

Why watts per kilogram matters

Raw watts move you on flat ground, but on climbs you fight gravity, so power relative to weight decides the pace. Divide FTP by your body weight in kilograms to get watts per kilogram: a 250-watt rider at 75 kilograms is 3.3 W/kg.

As a rough guide, recreational riders sit near 2 to 3 W/kg, keen amateurs around 3 to 4, and elite road pros exceed 5.5 W/kg at threshold. Improving your ratio means raising power, shedding excess weight, or both.

Worked with our own calculator

FTP calculator (cycling)

Given

Average 20-min power (W): 250
Body weight (kg): 70

Result

FTP (W): 238
Power-to-weight (W/kg): 3.393

These figures are produced by the calculator below, not typed in by hand — they are recomputed whenever the tool changes.

Run it on your own figures →

Frequently asked questions

What is a good FTP?: There is no single good number — it depends on your weight and goals. Watts per kilogram matters more: around 3 to 4 W/kg at threshold is a strong recreational level.
Do I need a power meter to know my FTP?: To measure FTP directly, yes — you need a power meter or a smart trainer that reports watts. Heart-rate-only estimates are rough because heart rate lags and drifts during hard efforts.
How often should I retest FTP?: Every four to six weeks during a training block. Testing too often gives noisy numbers; testing too rarely leaves your zones out of date as you get fitter.
Is the 20-minute test really an hour of power?: Taking 95 percent of a 20-minute effort approximates the power most riders could hold for an hour. It is an estimate, not a law — some riders hold closer to 90 or 100 percent depending on their physiology.

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