Different website elements like images

Understanding Content Layout Shift

When it comes to creating an optimal user experience on your website, understanding and managing content layout shift is crucial. This term refers to the unexpected movement of web page elements while the page is still loading. It’s a key factor in user experience and plays a significant role in Google’s Core Web Vitals.

Let’s delve into the world of content layout shift, exploring what it is, why it matters, and how you can manage it effectively to improve your website’s performance and user experience.

What is Content Layout Shift?

Content layout shift, or CLS, is a term used to describe the unexpected shifting of web page elements while a page is still loading. This can include anything from images and buttons to text blocks and ads. The shift occurs when elements on a page move from their original positions without user interaction.

CLS is one of the metrics Google uses to measure user experience on a website. It’s part of Google’s Core Web Vitals, a set of metrics that focus on loading performance, interactivity, and visual stability.

How is CLS Measured?

CLS is measured as a score, with 0 indicating no shifting and a higher score indicating more significant shifting. Google considers a good CLS score to be less than 0.1. A score between 0.1 and 0.25 needs improvement, and anything above 0.25 is considered poor.

The CLS score is calculated based on the impact fraction and the distance fraction. The impact fraction measures the viewport area that is affected by the shift, while the distance fraction measures the distance the elements have moved.

Why Does CLS Matter?

CLS matters because it directly impacts user experience. When elements on a page shift unexpectedly, it can be disorienting and frustrating for users. It can lead to accidental clicks or difficulty interacting with the website, resulting in a poor user experience.

Moreover, as part of Google’s Core Web Vitals, CLS can affect your website’s search engine ranking. Google has indicated that sites with a good user experience, including a low CLS score, may rank higher in search results.

The Impact of CLS on SEO

CLS is a crucial factor in SEO because it affects user experience, which is a key ranking factor for Google. A high CLS score can lead to a lower ranking in search results, while a low CLS score can improve your ranking.

Furthermore, with the introduction of Core Web Vitals, Google has made it clear that user experience metrics like CLS will play an even more significant role in search rankings in the future. This means that managing your site’s CLS is not just important for user experience, but also for SEO.

How to Manage CLS Effectively

Managing CLS effectively involves identifying the causes of layout shifts on your website and implementing strategies to prevent them. This can include things like specifying dimensions for images and videos, avoiding inserting content above existing content, and using CSS aspect ratio boxes.

Let’s explore some of these strategies in more detail.

Specify Dimensions for Images and Videos

One common cause of layout shifts is images and videos without specified dimensions. When the dimensions are not specified, the browser doesn’t know how much space to allocate for the element, leading to a shift when the element loads.

To prevent this, always specify the width and height for images and videos. This allows the browser to allocate the correct amount of space for the element, preventing shifts.

Avoid Inserting Content Above Existing Content

Inserting content above existing content can cause the existing content to shift down, leading to a high CLS score. This is often seen with ads or banners that are inserted dynamically.

To avoid this, try to avoid inserting content dynamically. If you must insert content, try to do so below the fold or in a way that doesn’t cause existing content to shift.

Use CSS Aspect Ratio Boxes

Using CSS aspect ratio boxes is another effective strategy for managing CLS. Aspect ratio boxes maintain the aspect ratio of an element, preventing it from resizing and causing shifts.

To use aspect ratio boxes, you can set the aspect ratio using CSS. This ensures that the element maintains its aspect ratio, regardless of the viewport size.


Content layout shift is a crucial aspect of user experience and SEO. By understanding what it is and how to manage it, you can create a more stable and enjoyable experience for your users, while also improving your website’s performance and search engine ranking.

Remember, a low CLS score is not just beneficial for your users, but also for your SEO efforts. So, start implementing these strategies today and see the difference it can make to your website’s performance and user experience.

Leave a Comment

Your email address will not be published. Required fields are marked *

Click to access the login or register cheese