Cycling IF calculator
Calculate your cycling Intensity Factor (IF) using your normalized power and FTP. IF shows how intense a ride was relative to your threshold: the same ride can feel very different to two cyclists.
Calculate my IFNormalized power at 80% of your FTP.
How IF is calculated
Divide the normalized power of your ride by your FTP, both in watts. The result has no units.
Normalized power
Summarizes the power of a ride while giving more weight to harder efforts, such as accelerations and climbs.
Functional threshold power
An estimate of the power you can sustain over a prolonged effort. Use a value that reflects your current fitness.
Intensity Factor
With an NP of 200 W and an FTP of 250 W, the result is 0.80. That NP equals 80% of your FTP.
Calculate the IF of a ride
Adjust your normalized power and FTP to see the result.
200 W ÷ 250 W
Your NP equals 80% of your FTP.
Why IF uses normalized power
Both rides last one hour and have an average power of 200 W. The second includes surges that increase its normalized power and, in turn, its IF.
Constant power
Variable power
Both examples use an FTP of 250 W. The second alternates 5 minutes at 100 W with 5 minutes at 300 W. These are simulated data; NP is estimated using 30-second rolling averages and the results are rounded.
Duration matters too
A one-hour ride and a four-hour ride can both have an IF of 0.80. The longer ride involves more work and may require more recovery. IF alone does not reflect that difference.
IF in Training Monkeys
You can add a reference IF to your cycling sessions alongside their duration and workout blocks. After the ride, your RPE and comments help your coach understand how it felt.
Frequently asked questions
Does an IF of 0.80 mean 80% of my maximum effort?
It means 80% of your FTP in terms of normalized power. It is not a percentage of your maximum power, heart rate or perceived effort.
Can IF exceed 1.00?
Yes. It means the NP for the period analyzed exceeds your FTP, which is possible during short efforts. If this happens consistently on long rides, review your FTP and data quality with your coach.
Is a higher IF better?
Every session has a purpose. A well-executed easy ride may be exactly what you need. IF describes relative intensity; it does not rate the quality of your training.
Can I calculate IF from average power or RPE?
Cycling IF requires normalized power and FTP, both in watts. Average power cannot replace NP. RPE is a separate, subjective measure; the two metrics complement each other but cannot be converted into one another.