If you’re running or maintaining a website, then you’re familiar with Core Web Vitals, a set of metrics designed to measure user experience on the web. One of the most important metrics, and certainly the most confusing, is cumulative layout shift (CLS).
What is Cumulative Layout Shift (CLS)?
To put it simply, CLS measures the visual stability of a website. It captures how much the layout of the web page shifts as it loads. Basically, if you’ve ever found a web page that shifted as you tried to click on a button, you’ve likely experienced a high CLS score.
Why Should You Care About CLS?
As most online users agree, a fast website is a great website. That’s why Google started including site speed as a ranking factor. But what good is a fast website if it’s clunky and the layout shifts all over the place? High CLS scores not only makes your website look unprofessional but also affects the user experience. It can be frustrating to click on a button that suddenly vanishes or moves to a different location.
How is CLS Measured?
Web developers use various metrics to measure website performance and load times. Similarly, CLS score is measured using the CLS metric. CLS is calculated by multiplying the impact fraction, which is the proportion of the screen affected by layout shift, by the distance fraction, which is the distance the elements shifted. This calculation is done for every instance of layout shift on the webpage, and the scores are summed up to get the cumulative layout shift, also known as CLS.
How to Fix CLS?
There are several ways to fix CLS score issues on your website. One of the most effective ways is to calculate the impact fraction. This will allow you to identify which element on the webpage is causing the layout shift. Once you identify it, you can adjust its size to fit perfectly in the allotted space.
Another approach is to preload your content. By doing this, your website will have more time to load the images, which will reduce the chances of layout shifts. Browser caching, layout reflow optimizations, and loading images using correct aspect ratios are just a few more solutions to minimize CLS.
CLS score is an essential metric to improve the user experience and website ranking. By understanding what CLS is, why it’s important, and how to fix it, you’ll be better equipped to make your website more visually stable.
We want to thank the thought leader Patrick Stox as the source for this content and such awesome teachings on the subject and we hope that this article can help you and your business! Here’s the link to his post https://ahrefs.com/blog/cumulative-layout-shift-cls/.
