Zwift FTP differs from Zwiftpower FTP

Hi All. I could not find an answer already posted so hopefully someone can help.

In a recent event, I received the message that my FTP had increased, to 291, I accepted that change. However in Zwiftpower it shows on my profile as 253 @ 73kg.

I followed the calculation of 3 best 20 min FTP over 90 days, by 90%, and I can see that the Zwiftpower number is accurate (accounting also for recent weight loss of 2kg). All these races were @ 75kg.

What I can’t now work out is, why Zwift said my FTP has incrased to 291 (this was after my most recent race at 75kg… and I have subsequently adjusted to 73kg and have had no races at this weight.)

Best I can work out is that the FTP suggested by Zwift is at 100%, but Zwiftpower takes 90%… but even with this I can’t quite get the numbers to line up.

Thanks.

Zwift power is just a manually entered value it doesn’t update, you have to update it manually.

Zwift power doesn’t use it for any calculation.

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There are a variety of ways of estimating FTP. I don’t know what calculation zwift uses. Zwift power is of course well documented. I think it’s unusual for them to vary hugely. You can always enter your own choice of value in zwift if you want. It is used for workouts.

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According to a Zwift Insider article (How to Adjust Your FTP on Zwift - Zwift Insider), here’s how Zwift’s in-game estimate is generated : « Your FTP value is calculated at the end of your ride as 95% of your highest 20-minute average power. »

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Thanks that is it. The difference is between the 90% of 20 minute FTP in Zwiftpower, and the 95% of 20 minute FTP shown in Zwift as “New FTP Detected”.

This sort of makes sense as the game will keep pushing you higher and higher so that eventually your calculated average power in Zwiftpower will improve :slight_smile:

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Hi
My problem is, ZP does not decrease the FTP after then latest FTP-Test in Zwift…ZP still says 324 (estimated)

You have to manually update your ZP FTP (Profile >>Settings >> FTP)

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I’m getting the opposite- my ZP is updating FTP increases but zwift isn’t updating or notifying me
Right now there is a difference of 12, with ZP calculating me higher

If you haven’t manually changed it (it will have estimate next to the number) ZP estimates based on the power curve it holds for you - your power curve is made up from your ZP captured events so unlikely to be an accurate indicator of FTP.

I usually wait for the Zwift one to pop up and don’t touch it
But the ZP one changes especially after some efforts