eFTP estimation

May be someone can help me to understand.
My eFTP on Rouvy is 372
My eFTP on intervals.icu is 328
There is a big gap, which one should I trust more ?
Both have same activities.

It depends on how the algorithm in each platform is assessing estimated FTP…I wouldn’t compare them or trust either of them.

Do a proper FTP test if you want to know your ‘real’ FTP.

I suggest a KM Progression 1 Test: The FTP Test: Physiology and New Protocols


higher. the right one, is always the higher one! :sunglasses:


You could model both power curves and choose which one you like. Go to (left menu) power → (top menu) power curves → Define Curve. Add 2-3 data points to add a modelled power curve to the diagram.

My instinct is the Intervals eFTP is more correct, partly because, maybe, Rouvy have more incentive to calculate higher (happier customer metric), and maybe because your Intervals account is pulling in data from other rides in addition to your Rouvy trainer rides? For example, Intervals has a nice feature to filter between indoor and outdoor rides—if all your indoor rides are on Rouvy I’d be curious if applying the filter in Intervals gives you a closer number.

What @Olly_Thomas said - the most reliable way to find out is to try to ride at your supposed threshold for 30mins+. Providing you are not starting off way too high, Kolie Moore’s tests are way easier than a 20min test.

With the default settings, the intervals eFTP can be based on a 3 min max effort. In my case that will overestimate FTP by 20-30W. I have my eFTP min duration set to 30 mins (1800 secs) most of the time, which means that the eFTP is pretty close to what I can actually maintain for 30mins+. The main downside is that eFTP only updates when I do long FTP test or a race, so can be a bit low at times.

Interesting reading, but did I miss something or does it not actually explain how to then calculate the ftp number from these tests?

From the article…

Your FTP will be equal to the average power of the entire test…

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Duh. I guess I was expecting something more complex as it mentioned using ‘WKO’ software.
I might try this next time.

What’s interesting looking at my power curves in intervals is I’ve never actually hit my ftp power for 60 minutes (I don’t race or try that duration, just 8 or 20 ftp tests) - regardless of level of fitness. And if I’m honest I’d say I probably couldn’t hold my ftp power for 60 mins

It you’re being honest, then chances are your estimate from an 8-min or 20-min effort is too high. So your easy rides become harder than they should as a result of a higher level/zone 2. Perhaps look at your 20-min power at about 90-93% and see how that relates to what you could do for an hour.

Then, if you’re honest, it’s not your FTP😉