Cycling FTP Calculator

What Is FTP (Functional Threshold Power)?

Functional Threshold Power (FTP) is the highest average power a cyclist can sustain for approximately one hour. It represents the boundary between aerobic and anaerobic exercise—the point where lactate accumulation begins to exceed your body's ability to clear it. FTP is expressed in watts and has become the gold standard metric for measuring cycling fitness and prescribing training intensity.

Developed by Dr. Andrew Coggan and Hunter Allen, FTP revolutionized cycling training by providing an objective, repeatable measure of fitness. Unlike heart rate, which varies with fatigue, heat, and caffeine, power output is direct and reliable. Knowing your FTP allows you to train at precisely the right intensity for any workout goal.

How FTP Is Calculated

Since sustaining a true 60-minute all-out effort is extremely difficult, most cyclists estimate FTP from shorter tests. The most common method uses a 20-minute test:

The 0.95 multiplier accounts for the fact that most cyclists can sustain slightly higher power for 20 minutes than for a full hour. Other test protocols use different multipliers based on the test duration and format.

FTP Test Methods

20-Minute Test: After warming up, ride as hard as possible for 20 minutes. Multiply average power by 0.95. This is the most popular and reliable method.

8-Minute Test: Perform two 8-minute all-out efforts with recovery between. Take the higher average and multiply by 0.90. Good for time-constrained testing.

Ramp Test: Progressively increase power every minute until failure. FTP is approximately 75% of your best 1-minute power. Quick but may overestimate FTP for some riders.

60-Minute Test: The gold standard—ride as hard as possible for one hour. Your average power IS your FTP. Extremely demanding and rarely performed.

How to Use This Calculator

1. Select the type of FTP test you performed
2. Enter your average power (or max 1-minute power for ramp test)
3. Optionally enter your body weight for W/kg calculation
4. Click "Calculate FTP & Zones" to see your results
5. Review your FTP and seven training zones

Worked Example: 20-Minute Test

A cyclist completes a 20-minute test with an average power of 260 watts:

Step 1: Record average power: 260 watts

Step 2: Apply 95% multiplier: 260 × 0.95 = 247 watts

Step 3: If cyclist weighs 70 kg: 247 ÷ 70 = 3.53 W/kg

Result: FTP = 247 watts (3.53 W/kg) - Solid recreational/amateur level fitness

Power Training Zones

FTP Benchmarks by W/kg

Watts per kilogram (W/kg) allows comparison between cyclists of different sizes:

• Untrained: 1.0-2.0 W/kg - New to cycling
• Recreational: 2.0-2.5 W/kg - Regular cyclist
• Amateur: 2.5-3.5 W/kg - Training consistently
• Cat 4/5 Racer: 3.0-3.7 W/kg - Entry-level racing
• Cat 3 Racer: 3.7-4.2 W/kg - Competitive amateur
• Cat 1/2 Racer: 4.2-5.0 W/kg - Elite amateur
• Professional: 5.5-6.5 W/kg - WorldTour level

How to Perform a 20-Minute FTP Test

1. Warm up (20 min): Easy spinning with a few short high-cadence efforts
2. Clear your legs (5 min): Three 1-minute efforts at 100% with 1-minute recovery
3. Easy spinning (5 min): Recover before the test
4. 20-Minute Test: Ride as hard as you can sustain. Start conservatively—you should feel terrible in the last 5 minutes
5. Cool down (10+ min): Easy spinning

Tips for Accurate FTP Testing

• Test when fresh—take a rest day beforehand
• Perform on a consistent setup (same bike, trainer, or course)
• Control environmental factors (temperature, hydration)
• Pace yourself—starting too fast leads to underestimating FTP
• Retest every 6-8 weeks or when fitness changes significantly

Using FTP for Training

Once you know your FTP, structure workouts around power zones:

• Base Phase: Primarily Z2 endurance with some Z3 tempo
• Build Phase: Add Z4 threshold work (2×20 min at FTP)
• Peak Phase: Include Z5 VO2max intervals (5×5 min)
• Race Season: Maintain with race-specific efforts
• Recovery: Z1 only between hard efforts

FTP vs Other Metrics

How FTP relates to other fitness measures:

• Heart Rate Threshold: Approximately your heart rate at FTP
• VO2max: FTP is typically 70-85% of your VO2max power
• Race Pace: Most criteriums above FTP; time trials near or at FTP
• Climbing: W/kg more relevant than raw watts on hills

Frequently Asked Questions

How often should I test FTP? Every 6-8 weeks during training blocks, or whenever you feel significantly fitter or after a break from training.

Why is my ramp test FTP higher than my 20-minute test? Ramp tests can overestimate FTP for riders with good anaerobic capacity. The 20-minute test is generally more accurate.

Can I estimate FTP without a power meter? Heart rate can provide rough training zones, but power provides much more precise and consistent data. Consider investing in a power meter for serious training.

Should I test indoors or outdoors? Indoors provides more controlled, repeatable conditions. Outdoor tests can be affected by wind, traffic, and terrain.

Limitations and Assumptions

FTP is an estimate of sustainable power, not an exact physiological measurement. The standard multipliers (0.95 for 20-minute, etc.) are averages—individual responses vary. Some cyclists may need to adjust multipliers based on their physiological profile. Ramp tests tend to favor cyclists with strong anaerobic systems and may overestimate FTP for endurance-oriented riders.

The training zones provided follow the Coggan/Allen model, which is widely used but not universal. Some coaches use different zone systems. FTP typically represents power sustainable for 45-70 minutes depending on the individual, training status, and pacing strategy. Use these calculations as a starting point and adjust based on real-world performance and perceived exertion.