1. To determine your critical power and W’, complete 2-3 maximal efforts, each lasting between 3-mins and 20-mins. We recommend 3-mins, 5-6 mins and 12-mins. You should try to pace these with a consistent power, avoiding a hard start or finish for example.

  2. Find your average power for each effort.

  3. Enter your test data into the calculator below. Be sure to enter the test duration in seconds and not minutes.

  4. Your results will then be automatically calculated. There are two sets of results based on whether you completed two or three tests. Make sure you’re looking at the correct section, depending on how many tests you did.

  5. In the Pacing Calculator section, you can generate estimates of the power you can hold over certain durations, and vice versa. This only works reliably for durations between 3-mins and 20-mins.

Critical Power Calculator

Critical Power Calculator

Test 1:
Test 2:
Test 3:
Input your test results in this section. Make sure you enter duration in seconds, and not in minutes!

If you only did two tests, then just enter results for Test 1 and Test 2.

Results - Two Test Solution

Critical Power (W):
Approximate FTP (W):
W' (kJ):
If you did two tests, your results will appear in this section. If you did three tests, you should read the results from the next section ('three test solution').

Results - Three Test Solution

Critical Power (W):
Approximate FTP (W):
W' (kJ):
Goodness of Fit (%):
If you did three tests, you should read your results from this section. We ideally want the 'goodness of fit' to be above 97%, which indicates your test efforts were all well-paced.

Pacing Calculator

Use this section to estimate the power you can hold for a given duration and vice versa. This only works for durations between 3-mins and 20-mins (180-1200 seconds). Make sure you look at the appropriate section (two test solution if you did two tests, and three test solution if you did three tests).
Enter Target Duration (s):
Estimated Power (W) (Two-Test Solution)
Estimated Power (W) (Three-Test Solution)
Enter Target Power (W):
Estimated Duration (s) (Two-Test Solution)
Estimated Duration (s) (Three-Test Solution)

Further Coaching

It’s important to strike a balance between speed, threshold, and endurance workouts in order to meet the needs of your target races.

Maybe we can help?