How to determine your W’ (missing calculator)

You must do these 2-things

  • Ride as hard as you can for approximately 3-minutes, keep going if you can go longer than 3
  • Find an 8 to 20-minute max effort
  • Alternatively, you can put your FTP in the second box and enter 40 minutes.

Then just plug those values into our calculator


  • This came from the GoldenCheetah Sweatpy project. We use the 2-parameter non-linear method.

You can always hop on your trainer, do a solid warm-up and go as hard as you can for these efforts. Try to pace yourself so it is even power and see what your average power is. You can repeat this a few times over a couple of weeks to get your maximum value. With practice, your pacing will be better and your W’ will get more accurate.

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Find your best efforts in Strava or TrainingPeaks without another test

If you ride close to failure recently in shorter duration efforts, you can use your best efforts.You must have a shorter one (around 1-minute) and a longer one (around 3-minutes). Pushing it hard on a hill is a good place.

You can use Strava Summit or TrainingPeaks premium to give you your best efforts and many other options, i.e. GoldenCheetah. These will show you your best average power for X minutes.

Obviously, you must have a power meter for this activity.

A simple way to find your W’

Here is a workout that is like a ramp test that would be fairly easy to determine your W’ based on your failure point. In the workout description, I describe how to just play with the numbers after your workout to find your W’.

* I will add an improved video shortly on how to use any of these methods.


What Now?

Once you know your CP and your W’ you can use the features on our workout creator and to find or create the perfect interval workouts for your fitness profile. View the next article to learn more.

Next Article — Part #3

A quick 2-minute video showing you how to determine your estimated W’ from GoldenCheetah or XERT.

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