Skip to main content

What impact does Google PageSpeed Insights have on SEO?

14 Aug 2021

The impact of PageSpeed Insights on SEO. A topic discussed plenty of times on all sorts of blogs and forums. By some, a hated system that has absolutely no positive value. Some, on the other hand, devote their entire professional lives to optimizing pages in this way, in order to get 100 points in Google PageSpeed Insights. Spora liczba specjalistów SEO twierdzi, że wynik ten nie ma kompletnie żadnego odzwierciedlenia w rzeczywistości.  Twierdzą, że są skuteczniejsze narzędzia do określenia realnej prędkości strony internetowej. Druga część jest zdania, że narzędzie to, jest jedynym wyznacznikiem prędkości i płynności działania strony.  Ma również ogromny wpływ na pozycję witryny w wynikach wyszukiwania.

Who is right?

One and the other. I am already explaining why. However, first I would like to point out that the presented advantages, disadvantages and how the Google PageSpeed Insight tool works were tested personally by me on a "living organism", i.e. in the process of creating my website. Before we get to the crux of the matter, i.e. the question of whether it is worth suggesting this tool for SEO optimization of the site, I will briefly describe what Google PageSpeed Insights is, how it works, in general "what it's up against".

What is Google PageSpeed Insights?

As we can read on the official website, Google PageSpeed Insights is raportuje wydajność strony zarówno na komputerach jak i na urządzeniach mobilnych, a także podaje sugestie jak można ją ulepszyć.  Test każdej publicznie dostępnej strony www możemy wykonać pod adresem:

The Google Page Speed Insights results screen looks like this:


As you can see when you enter the page, you type the name of the site or one of its subpages and click the analyze button. After a while we get the result in the form of a pie chart. Separately for computers and separately for mobile devices. The graph takes one of three colors: red - poor optimization of the site, yellow- average optimization and green– dobra optymalizacja.  Mniej doświadczony użytkownik, nie mający na co dzień styczności z SEO, zazwyczaj swój test witryny zakończy na wykresie, z którego wyczytać może w jakim stanie jest testowana witryna. Ja chciałbym jednak opowiedzieć, jakich szczegółowych informacji dostarcza nam ów test. W jaki sposób mogą się one nam przydać w celu poprawy i optymalizacji naszej witryny oraz jaki impact Google PageSpeed Insights has on SEO

What information does the analysis provide us with?

After performing the test, we were shown a graph, which we can see in the image above. However, the most important and useful information for us is a bit below. After scrolling the scrollbar, the lab data of the tested site will appear before our eyes. A section called capabilities and a section called diagnostics. Below I will discuss each of the parameters that are displayed after the analysis and tell how, from my point of view, the improvement of a particular element affected the functioning of the site.

Laboratory data

All analysis is based on the Lighthouse engine. Lighthouse is an automated open source tool for improving the quality of websites. It can be run on any website, public or requiring authentication. It has audits for performance, accessibility, progressive web applications, SEO and more. The lab data section displays 6 columns that display the results of the analysis.

dane laboratoryjne

First Contentful Paint

First rendering of content. FCP measures how long it takes the browser to render the first piece of DOM content when a user navigates to your site. These include images or svg files, for example.


Speed Index

The speed index measures how fast content is displayed visually when a page loads. Lighthouse first captures the video of the page loading in the browser and calculates the visual progression between frames. Lighthouse then uses the Speedline Node.js module to generate the Speed Index score.


Largest Contentful Paint

The largest content rendering oznacza czas, w którym  wyrenderuje się największa treść na stronie np. obraz lub tekst.


Time to interactive

The time it takes for a page to become interactive. This parameter specifies how long it takes for a page to become fully interactive. A page is considered fully interactive when:

  • The page displays useful content, which is measured by FCP
  • Event handler programs are recorded for most visible page elements
  • The site responds to user interactions in under 50 milliseconds.

Total Bloking Time

The difference between the time to first render FCP, content and the time to full TTI interactivity.


Cumulative Layout Shift

Cumulative layout shift s a measure of the movement of elements in the visible area. CLS measures the sum of all individual layout shift results for each unexpected layout shift that occurs during the entire lifetime of the page. A layout shift occurs each time a visible element changes its position from one rendered frame to the next.


(Chrome User Experience Report).

Above the lab data, we can see the same parameters, but measured with another tool - CrUX (Chrome User Experience Report).). In short, this tool examines all the parameters described above, but not with a simulated test as in the case of Lighthouse, but based on the physical visits of users to a given site. So with this tool we have very reliable and reflective measurements of reality. The only disadvantage of this tool is that the site must "exist" for some time on the Internet and must generate traffic in order for the CrUX tool to have data on which to display the results. Translated with (free version)

Capabilities and Diagnostics

These two sections contain potential opportunities to improve the listed elements that should improve your Lighthouse score. Over the past few weeks I have been heavily involved in optimizing my site to get the highest possible score on the Lighthouse test. On computers I managed to get a score of 99-100, while on mobile devices I managed to get a score of 90-95. In my opinion, a satisfactory result, but it took some work to be able to boast such a score. As I mentioned in one of the first paragraphs, those who are not convinced by the Google PSI tool and those who think it is a very important indicator of both are right.

Effect of the result on the actual speed of the page

Z mojego doświadczenia wynika, że warto jest uzyskać wynik „na zielono” tzn. powyżej 90 punktów.  „Gołym’ okiem widać różnicę pomiędzy czasem ładowania strony. przed optimizing it was in the limit of even 5-6 seconds. After applying the tips and optimizing some elements, the loading time of my site dropped to 0.5 seconds. However, there is also the other side of the coin. There is no need to exaggerate and try at all costs to achieve the magic score of 100 points, at the expense of reducing the functionality of the site. From what I personally noticed, and it is quite strange to me, many dedicated Google or Facebook solutions for example Google Maps module, Facebook profile sharing module on the page, in a very strong way reduced the Google PageSpeed Insights test score. As you can read in the article by pasting the Google Play store link and running the test we get a score of just a few percent. So, as we can see, even Google's developers did not pay attention to the Google PSI test result.


The impact of Google PageSpeed Insights on SEO.

I recently came across a very interesting article that may change some skepticism about the Google PageSpeed Insights test score. As we can read in the article Google is going to make some changes regarding search algorithms in 2021These changes will certainly affect the position of sites in search resultsNamely, the idea is that more emphasis will be placed on User Experience (user experience while using the site)What follows is the site's loading speed, its fluidity and its adaptation to mobile devices. It is all these parameters that the test made with the Lighthouse engine checks. I think it is worthwhile to take an interest in this topic and optimize swoją witrynę chociaż do wyniku powyżej 90%.  W przyszłości może się to okazać bardzo dużym wyznacznikiem tego jak wysoko w wynikach wyszukiwania będzie wyświetlała się nasza witryna.

You may find that two similar sites, one of which is very well optimized for UX. However, it is lower in the search results. The other, on the other hand, loads much slower, doesn't quite display correctly on cell phones, but is several positions higher in the search engine. After the 2021 algorithm changes, it may be that the better-optimized site will skyrocket in Google's rankings, while the other less-optimized site will drop a few "eyes" down. If you want to learn more about optimizing the content on your website and want to improve your score in Translated with (free version) Google PageSpeed Insights is  check out our offer


The Google PageSpeed Insights is tool has its pros and cons. In my experience, it is strongly useful. I used it when improving the fluidity and speed of my site, which translates very much into User Experience. Another aspect in favor is the fact that in 2021 there will come changes regarding the operation of search algorithms. The changes that will be made to the search algorithm will "take into account" all those parameters that the Lighthouse engine test checks. A well-optimized site will be displayed higher in search results. On the other hand, let's not get crazy. Let's not try to achieve 100 points in Google PSI at all costs, at the expense of reducing important functionality of the site. We need to find the golden mean. Keep all the important functions and content of the site, but make them display in a user-friendly way.

Did you like our article? Check out other blogs