Which score is most reliable (and complete) to use when comparing different sites and pages to get a quick idea (e.g. between competitor websites without detailed analysis)?

I am asking because for the same page on the same site, the score is over 30 marks higher via Google Insights online, which leads me to believe that the official Chrome extension is more accurate (e.g. worse score).

Some of this has been addressed in detail before, but for the purposes of doing quick analysis — what accounts for the different PageSpeed scores?

  • Could you provide the URL that is giving such a different score between the two tools? Jul 5, 2013 at 14:18
  • @TimFountain, this site is awarded 47 in the extension, and 73 online
    – Baumr
    Jul 5, 2013 at 14:53
  • For that URL I get 76 from the extension, 73 online. Might you be logged in to the site and seeing slightly different content to the tool? Jul 5, 2013 at 14:59
  • Nope, definitely not — got 60 in Firefox
    – Baumr
    Jul 5, 2013 at 15:16

1 Answer 1


The difference between the scores is simply the different methods that the score is compiled between accessing them on a web browser and accessing them on a Google server. On the Google server everything is tuned and purposed specifically for the task of performing speed tests whereas the browser plugin depends on the browser and operating system, every single different instance of which can vary greatly and can contribute to page speed issues which can't be accounted for through the plugin.

If all you are wanting is a very quick 5 second check of the speed or the site you are trying to check is hosted on the localhost or in a protected environment Googlebot doesn't have access to then use the plugin, but if you are after a more accurate and up to date assessment (PageSpeed Insights is updated live as opposed to the Chrome plugin which is updated by regular releases) then go for PageSpeed Insights.

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