Difference Page rendering time and Page generation time

What is the difference between: Page rendering time, Page generation time and Time to interact?

I can’t find more info in the documents or in the forum here.

Which metric shows me the real user page load time? I think Page rendering time but I am not sure. Can someone please explain me the difference between these 3 metrics?

Thanks a lot :slight_smile:


Hi :slight_smile: The definitions are available here: List of dimensions and metrics | Piwik PRO help center

Hello Kuba, yes I already read that info but it’s still not clear for me.

For example:

Page generation time: The page loading time on the visitor’s device.
Page rendering time: The time taken to create the render tree, layout, and finally draw the website in the browser.

Isn’t that the same??

Here you have a nice graph showing all the points in time: Capturing RUM Metrics | Online Help Site24x7

To answer your question - we have to distinguish time needed to display the content and time needed to the point when the content will be interactive. Here’s also a nice article describing it.

I have read the info on

thanks for the link!

Now I think my confusion has to do with the way PiwikPro reports handle these pagespeed values:

  • In the report Pages i can select Pagespeed and then I see the Average page generation time value.

  • But in the report Website performance/Page timings the metric Average page generation time is not even there! Instead I see the Average page rendering time.

This is very confusing! I think it would be better to use Average page generation time in both the Pages/Pagespeed report and Performance reports.

That being said, if I understand the difference correct now then:

  • Page generation time is the same has what is called Load Time in the linked article.
  • page rendering time is the same as what is called Rendering Time in the linked article.

So Page generation time is the time after which the user can see everything on the page, but not everything is loaded at the back-end?

Page rendering time is the time after which the user can see everything on the page, and everything is also completely loaded on the back-end and the page is interactive?

If this is correct then why not change the name Page generation time into Page load time? That would be a lot clearer in the PiwikPro reports, because Page rendering time and Page generation time sound a lot alike and is confusing (at least for me).

Page generation metric was available there for years. We added additional metrics later on and wanted to keep backward compatibility. Maybe that’s a good timing to clean it up. Thanks for suggestion, I’ll pass this feedback to the development team.