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    A website should be like a good car, not only visually attractive, but also fast. Unfortunately, in the vast majority of cases, websites full of “fabrics” do not meet the second condition. The answers to the question of why this is the case are many, to explain this let’s start with the basics, that is, what is the optimal page load time. 

    page load time vs seo

    How long should a website load? 

    The answer to this question is not clear-cut, the most sensible seems to be to follow the rule “the faster the better”. According to Google’s research, the most optimal page load time is between 2 and 3 seconds, because after that time more than 40% of users simply leave the site without waiting to see it in full. A time of more than 5 seconds is far too long, and it will affect both user behavior on the site and positions in organic search results. 

    Short page load times are especially important for mobile devices. Research on the behavior of Internet users on these devices shows that they are less “patient” than desktop users (even though in many cases they are the same users). Simply by using a browser on desktops, we are willing to wait a little longer for the entire site to load than, for example, on a cell phone. 

    Page-loading-time-a-rule Mobile Index First

    Practice shows that in the context of excessive page load time, the main problem of the vast majority of websites is their mobile version. It is very often the case that sites that have adequate loading times on desktop, however, do not meet these conditions on mobile. This is particularly problematic in the era of the Mobile Index First rule, which Google began to introduce in 2018, and from 2020 applies to all indexed sites. 

    This rule in practice means so much that the most important version of a site affecting positions in organic search results is the mobile version, which is quite the opposite of what it used to be. Google decided to take this step because of the changing behavior of users using the search engine. The number of people using Google search on mobile long ago exceeded 50%. So this, rather than any other decision by Google, seems to be the most sensible solution. However, it has put page load time very high among the ranking factors affecting a site’s position in organic search results. 

    How to check page load time?

    Since we already know how important page load time is, let’s consider how we can effectively check it. Here Google itself comes to our aid with its Page Speed Insights tool. This is a tool dedicated precisely to verifying all the problems of websites, related to their loading. When we enter the address of our site into this tool, we get two separate analyses – one for mobile devices, the other for desktop devices. 

    What can we basically learn from the Page Speed Insights tool? 

    The first information Google presents to us for both versions of the site is the “Core Web Ratings”. Here we are dealing with three Core Web Vitals indicators (LCP, FID, CLS) whose results, Google shows based on data from the last 28 days. In a nutshell, these indicators are supposed to assess how the site is functioning technically and how realistically the user is using it. 

    The next segment is already site performance, which already consists of several specific elements and tips for improving site performance:

    – Performance rating – presented on a scale of 1 to 100, where 1-49 is a score of very bad, 50-89 average and 90-100 very good. If we see a score below 50 after Page Speed Insights has checked our site, it means that we need to take specific corrective measures if we want our site to be visible in organic search results. The performance rating also comes with a calculator that will allow us to see how an improvement/deterioration in any of the factors will affect our score. 

    – Performance data – among which there is such information as – time of first content rendering, time of full page interactivity, speed index, time between first content rendering and full interactivity, time of rendering largest content/image, measure of movement of elements in visible area

    – Page loading diagram – which is simply a visualization of how the site is visible to users in the first seconds of its loading

    – Diagnostics and opportunities for improvement – the most important part of the analysis – Google directly tells us what we can fix and by how much it will actually shorten the loading time of our site, these are the data in which it is worth reading very carefully and from them just start drawing conclusions about what really delays the performance of our site. 

    What are the most important factors affecting page load time?

    There are several of them, of course, and they affect page load time differently depending on how much they exceed the accepted standard:

    – Images – more specifically, their size and the format in which they are posted on the site. The most common mistake is to publish images on the site in old-fashioned formats (jpg, png), which hinder their better conversion. The second most common mistake is, of course, publishing images without compressing them beforehand, which makes them sometimes several MB instead of a few KB. Such actions significantly increase the weight of the site itself, which of course translates into loading. 

    – The lack of lazy loading of images – the so-called “lazy loading” causes all the most important elements to load first, then only those hidden or outside the main screen. Thanks to such an action, we are able to reduce the time needed for full interactivity of the site. 

    CSS and Java script blocking page rendering – it is very common that all CSS and Java script elements start loading at once, which significantly delays the loading time of the entire content. It is worth remembering that only critically necessary elements should load first, the rest should be delayed.

    – No restriction of unused java script – only the necessary java script should run when the page is loaded, all others should run only when needed. 

    – No restriction of unused CSS code – here, as in the case of java script – only what is necessary at the moment should run. 

    – Too many redirects – excessive 301 redirects can also cause delays in page loading

    – Too many CMS plugins – it’s worth verifying that all the plugins installed for our CMS are actually needed.

    What else besides SEO has an impact on too-long page load time?

    As you can easily guess it is, of course, UX (User Experience). When a user has to wait too long for a page to load, they will simply abandon it and head to another search result related to their query. Because of this, excessive loading times are one of the reasons for high rejection rates for many websites. The development of technology has caused us to change very much the boundary of patience and the definition of what “long” means in the context of loading a page. As I mentioned earlier this is especially evident on mobile devices. 

    In research conducted by Google, users clearly declare that if a page takes too long to load they will abandon a purchase. This, combined with Google’s restriction of high rankings in natural search results for such sites, can result in a significant drop or even no organic traffic to the site, which will of course translate into fewer conversions. 

    The number of conversions will decrease.

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    Adrianna Napiórkowska
    Adrianna Napiórkowska

    She has 11 years of professional experience, she started her career at the Emarketing Experts agency as a junior SEO specialist. In addition to website positioning, she was responsible for conducting 360° marketing projects as an Account Manager at She worked for companies from the financial sector (Bank Millennium, Bank Meritum, Finai S.A.) and e-commerce (e.g. Black Red White, Autoland, Mumla). At Up&More, he is responsible for, among others, SEO projects for Panek Car Sharing, Amerigas, Interparking, H+H and Autoplaza.