# FTP Test Question



## Bspboy (Aug 19, 2017)

Hey everyone. I just finished an FTP test on Zwift. When the test started it showed my average watts on the screen. Right before the end I was at 183 watts. But then when I finished it said "Your FTP is 175 watts". Why is my FTP lower than the average I got? Thanks!


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## ceugene (Jun 20, 2015)

Because the test is 20 minutes long and your FTP is the power you would put out over 1 hour. The basic formula is your 20min power x 0.95.


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## tlg (May 11, 2011)

FTP (functional threshold power) is the maximum power you can sustain for one hour. 
You could do a one hour test if you want the most accurate number. 
But studies have shown that if you do a 20 min test and reduce it by 5% it's about the same as a one hour test.

https://support.zwift.com/hc/en-us/articles/210208083-What-is-FTP-and-how-is-it-used-in-Zwift-
In order to determine your FTP, Zwift provides you with a few different options:


The full 60 minute FTP test
An abbreviated 20 minute FTP test (takes 95% of your avg. power over 20m)


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## Bspboy (Aug 19, 2017)

Yeah I did the 20 minute one.


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## pedalbiker (Nov 23, 2014)

FTP isn't defined as being your one hour power. It's a bit more complicated than that. And it's surely not your 20 min power x some generic formula, unless it just happens to coincidentally be that. 

In any case, it doesn't matter. If you're following some generic workout plan, then just see how you get on with that. If it's too hard, take 10 watts off everything. Too easy, add 10 watts, etc. The more you do it, the better you get at doing it. But I wouldn't' get too hung up on the minutiae. 

Consistently riding your bike and increasing the amount of time you do that will see you get better even if you never did a single XXX watts interval.


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