I put two files in and got the same number (269w). CP and FTP are essentially equal from what I've read.

Critical Power#5 (Critical Power) is also a very useful means of estimating FTP. It explores the relationship between work performed (kJ) and duration (seconds). Essentially all you need is at least two (or more) maximal efforts of at least three minutes and less than 30 minutes duration, say one of five minutes and another of 20 minutes, although the choice is arbitrary and up to the individual. You then enter the average power and durations ridden into the Critical Power model. The model will calculate what is called "Critical Power", which is essentially equivalent to FTP (or at least a very good estimation of FTP).

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