The term CLS may bring to mind a Mercedes model. This time, we're not talking about the automotive industry, but about a parameter that plays a crucial role in SEO. However, it's undeniable that a good CLS metric on your website is worth striving for just as much as a luxury car. Learn what this metric represents and how to effectively optimize it on your own website.
What is CLS?
Your brand's visibility in search engines depends on meeting as many criteria as possible (Core Web Vitals), which Google's algorithm uses to rank websites. SEO, therefore, aims to ensure your website meets the highest standards. There are many factors to evaluate, and one of them is CLS, or Cumulative Layout Shift.
This enigmatic factor is nothing more than a measure of visual stability. It determines how often users experience unexpected changes in the position of individual interface elements. Ideally, all website content should load equally quickly. However, on less optimized sites, some elements often appear with a delay after the interface has initially loaded. Therefore, every effort should be made to eliminate such imperfections.
Why is it necessary to take care of Cumulative Layout Shift?
To further illustrate the importance of this metric, it's worth putting yourself in the shoes of a user visiting a website. Let's use an example. Imagine you're about to click a button, and at the last moment, an additional banner is loaded. This lands you in a completely different place than you expected.
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As a rule, internet users' patience wears thin very quickly. Sometimes, even minor imperfections are enough to make someone abandon their interest in your offer. A poor CLS can, therefore, mean you lose the opportunity to acquire a new customer.
In addition to user experience, Google's robots' readings also matter. If the algorithm scanning your site detects poor CLS, it can result in a lower search engine ranking in favor of your competitors. Therefore, CLS can be considered a parameter that straddles UX and SEO.
How to measure the CLS factor?
Google considers a good CLS score to be no more than 0,1. A score below 0,25 puts you among the worst performing sites. Anything between these ranges is considered average and therefore requires improvement. The score is calculated based on the following factors:
- size of images,
- dynamic content, e.g. advertising banners,
- fonts with variable styles,
- loading time of individual elements embedded on the page.
When taking measurements, the distance and influence components are important. The former refers to the distance between the actual position and the initial position. The latter, on the other hand, concerns the extent of the space occupied on the device's screen.
How to check CLS?
Google provides comprehensive tools for monitoring your current CLS metrics. The first option is Page Speed Insights. Simply run an analysis using this tool to obtain data for both mobile and desktop devices.
An alternative solution is Lighthouse Tools, a plug-in that works in Google Chrome. After installing this tool, go to the tools menu and then expand the developer tools section. There, you'll be able to generate a report. The summary will include results that also include the CLS of the analyzed page. It's worth noting that Lighthouse Tools allows for more detailed results than Page Speed Insights. This makes it an excellent solution for advanced SEO specialists who know how to use precise data.
How to improve CLS?
Now that you know what CLS is, it's time for the highlight: practical tips for improving your website optimization. Review the guidelines below.
- Assign exact dimensions to images
Many of the imperfections that lower the CLS score are a consequence of using images with imprecise dimensions. Such elements can dynamically change their layout depending on the device being used. As a result, their positioning can sometimes be difficult to control. The solution is to specify a specific size. Use the "width" and "height" parameters for this purpose.
- Keep your ads in check
Dynamic ad formats have gained significant popularity in recent years. Their secret lies in adapting to the viewer's preferences. However, it's important to note that such creatives can create clutter on a website and thus lower the CLS. Therefore, it's worth designating a specific space for ad presentation.
- Avoid dynamic templates
When choosing a pre-made template, opt for a static option. Try to follow similar principles if you want to use a custom theme. A limited number of spectacular effects doesn't necessarily mean it's harder to impress your audience. Usability is a priority on the internet, and minimalism remains valuable despite the passage of time and changing trends. Users will certainly appreciate the clarity and readability of the interface.
- Make sure your fonts are loaded
Opt for a key font preload. This involves preloading the fonts you'll use. This way, your website won't have to constantly download typography data from the server. This will have a positive impact on both page loading speed and the coherence of the entire interface.
- Avoid asynchronously loaded elements
Sometimes, a creative design concept for a page might involve delaying the loading of some content. While these techniques can be effective, they negatively impact the Cumulative Layout Shift. Therefore, if you want to achieve the highest possible search engine ranking, it's best to avoid these kinds of changes.
Summary
The above article covers the following topics:
- Definition of the CLS index as a measure of the visual stability of a website
- The importance of CLS optimization for user experience and search engine positioning
- Methods of measuring the CLS coefficient and interpretation of the obtained results
- Google tools for monitoring CLS on websites
- Practical techniques for improving CLS, including optimizing graphics, ads, templates, and fonts
