Brandon Almeda - Author
Brandon Almeda
  • Sep 4, 2023
  • 2 min read

Improve Conversion Rates with CLS Minimization

grey flat screen computer monitor - CLS Minimization

Photo by Eftakher Alam on Unsplash

CLS Minimization

In the world of web development, improving user experience is of utmost importance. One aspect that greatly affects user satisfaction is Cumulative Layout Shift (CLS). CLS occurs when the layout of a web page dynamically changes while the user is interacting with it, resulting in a jarring experience.

CLS is especially problematic for websites with images or ads, as these elements often load slower than the rest of the page. Each time an image or ad loads, it can cause the content to shift unexpectedly, frustrating users who might accidentally tap on an unwanted element.

To mitigate CLS and ensure a smooth browsing experience, web developers need to focus on CLS minimization techniques. By prioritizing performance optimization, optimizing resource loading, and implementing various best practices, it is possible to minimize CLS and enhance user satisfaction.

In this article, we will explore the different strategies and techniques that can be employed to minimize CLS. We will delve into understanding the root causes of CLS, such as image and video loading, font rendering, and asynchronous scripts. With these insights, we will discuss practical approaches and solutions to reduce CLS, including optimizing element dimensions, fixing element positions, and using loading placeholders.

By implementing CLS minimization techniques, web developers can significantly enhance the user experience and improve key performance metrics. With our comprehensive guide, you will gain invaluable insights on how to tackle CLS issues and ensure a visually stable and seamless browsing experience for your users.

Understanding Conversion Rates and CLS

One crucial aspect of website optimization is maximizing conversion rates. Conversion Rate Optimization (CRO) focuses on improving the percentage of visitors who complete a desired action, such as making a purchase or subscribing to a newsletter. A critical factor in CRO is page performance, as slow-loading pages can significantly impact conversion rates. This is where Cumulative Layout Shift (CLS) comes into play.

CLS measures the visual stability of a web page during the loading process. It quantifies the extent of unexpected layout shifts that can cause confusion or frustration for users. When elements on a page suddenly move or shift as other content loads, it undermines the user experience and may lead to lower conversion rates.

By minimizing CLS, website owners can enhance the overall performance and user satisfaction. One effective strategy is to ensure that all resources, such as images or iframes, have predefined dimensions. This prevents sudden shifts caused by late-loading content. Additionally, asynchronous loading of third-party scripts and optimizing CSS delivery can also mitigate layout shifts effectively.

A positive correlation exists between page loading speed and conversion rates. Swift loading times not only enhance user experience but also boost search engine rankings. Search engines prioritize websites that offer better user experiences, leading to increased organic traffic and potentially higher conversions.

To assess CLS and its impact on conversions, it is vital to monitor key performance indicators (KPIs). Tracking metrics such as bounce rate, time on page, and conversions allow website owners to identify improvements areas. Conducting A/B tests where different versions of a page are evaluated by real users can provide significant insights into which designs minimize CLS and maximize conversion rates.

In conclusion, understanding conversion rates and their relationship with CLS is a fundamental aspect of website optimization. By focusing on minimizing CLS, website owners can enhance user experience, improve search engine visibility, and boost conversions. Continually monitoring KPIs and conducting A/B tests are effective approaches to iteratively improve layout stability and conversion rates.

The Impact of CLS on User Experience

Cumulative Layout Shift (CLS) is a key metric used to measure the visual stability of a web page during the loading process. It refers to unexpected shifts in page content, such as images or buttons moving around, causing frustration and confusion for users. Minimizing CLS is crucial for delivering a smooth and enjoyable user experience.

When CLS is high, users may struggle to interact with elements on the page, leading to a decrease in engagement and conversions. Visitors are more likely to abandon a website that exhibits frequent layout shifts, negatively impacting bounce rate and average session duration. This, in turn, can harm search engine rankings as algorithms prioritize pages that satisfy user intent.

Moreover, CLS can impact the accessibility of a website. People with disabilities who rely on assistive technologies may find it challenging to navigate through content that suddenly shifts around. Accessibility is an important aspect of inclusive web design, so minimizing CLS improves the experience for all users.

To optimize user experience and tackle CLS, several best practices can be employed. Firstly, setting dimensions for media elements, such as images or videos, prevents them from changing size during loading. Next, loading and preloading content with appropriate placeholders can maintain layout stability. Additionally, deferring JavaScript execution, especially for non-critical tasks, allows visual elements to load before any potential layout changes.

Improving CLS not only enhances user experience but also contributes to overall website performance. Google's Core Web Vitals, which includes CLS as a key metric, has become an essential factor in search rankings. By minimizing layout shifts, website owners can foster engagement, retain visitors, and improve their chances of ranking higher in search engine results, driving more organic traffic to their site.

Methods to Minimize CLS

Cumulative Layout Shift (CLS) can negatively impact user experience and search engine rankings. Fortunately, there are several effective methods to minimize CLS and ensure a smooth browsing experience for users. Implementing these strategies will not only improve website performance but also boost SEO rankings.

1. Set Dimensions for Media Content

By providing explicit dimensions for media elements like images and videos, you prevent them from shifting and causing unexpected layout changes. This can be achieved by adding width and height attributes or using CSS to specify the dimensions.

2. Preload Web Fonts

CLS often occurs when web fonts cause text to reflow. Preloading web fonts with the rel=preload attribute ensures they are loaded before the browser starts rendering, minimizing the chances of layout shifts.

3. Load Elements Before JavaScript Execution

JavaScript execution can introduce CLS if it modifies the layout before other elements are loaded. To prevent this, ensure that critical elements, such as headers, images, and other content, are loaded and rendered before JavaScript execution.

4. Prioritize Loading for Above-Fold Content

Load vital, above-the-fold content first to give users a quick and stable visual experience. By prioritizing the loading of essential elements, you reduce the likelihood of later elements causing a sudden shift.

5. Reserve Space for Ads and Embedded Content

Advertisements and embedded content often contribute significantly to CLS. Allocating space for these elements beforehand, using CSS padding or aspect ratio containers, helps maintain a stable layout when they load.

6. Use Animations and Transitions Carefully

Transitions and animations can lead to layout shifts, especially when applied to above-the-fold content. Be mindful when using such effects and ensure they don't cause unexpected shifts during page load or user interactions.

7. Test and Monitor

Regularly test your website using tools like the Web Vitals CLS diagnostic report. By monitoring and identifying areas with high CLS, you can pinpoint the sources and apply necessary optimizations.

By implementing these methods, you can effectively minimize CLS and enhance user experience. Optimized websites with minimal CLS tend to have higher SEO rankings, resulting in increased visibility and improved user satisfaction.

Best Practices for Web Design and Development to Improve Conversion Rates

Conversion Rate Optimization (CRO) is crucial for businesses looking to maximize the impact of their online presence. One key factor in achieving higher conversion rates is optimizing the Cumulative Layout Shift (CLS) on your website. CLS refers to the unexpected layout changes that occur during the page loading process, often frustrating visitors and leading to lower conversion rates. To help you minimize CLS and improve conversions, here are some best practices for web design and development:

  1. Prioritize Responsive Design: Ensure your website is responsive across various devices and screen sizes. Responsive design prevents layout shifts caused by elements not fitting or adjusting properly on different screens.

  2. Optimize Images: Reduce image sizes without compromising quality by leveraging modern image formats, such as WebP. Use tools or plugins to lazy load images, meaning they only load when users scroll to them, eliminating sudden shifts caused by image loading.

  3. Minimize Third-Party Code: Evaluate the third-party scripts and plugins you use as they can significantly impact CLS. Remove or minimize unnecessary scripts or defer their loading to prevent delays that cause layout shifts.

  4. Avoid Rendering Dependencies: Keep critical above-the-fold content independent from external scripts or stylesheets. This ensures that users see important content immediately, decreasing the chance of layout shifts during loading.

  5. Optimize Font Loading: Prevent sudden text layout changes by applying font-display: swap in your CSS. This displays fallback fonts while the desired fonts load, ultimately reducing CLS.

  6. Set Dimensions for Media: Specify dimensions (width and height) for media elements like images, videos, and iframes. This allows space to be reserved for the media, eliminating shifts when it loads.

  7. Preload Key Resources: Utilize the <link rel="preload"> attribute to prioritize essential resources. Preloading fonts, critical CSS, or JavaScript can improve loading efficiency and minimize layout shifts.

  8. Test and Monitor: Regularly assess your website's CLS using tools like PageSpeed Insights or Lighthouse to identify and address any CLS-related issues. Continuously monitoring CLS metrics will allow you to track improvements and make necessary adjustments.

By implementing these best practices, you can significantly reduce CLS and create a seamless browsing experience, thereby increasing your website's conversion rates. Remember, a visitor who experiences minimal layout shifts is more likely to stay engaged, leading to improved user satisfaction and higher conversions.


In conclusion, CLS minimization is a crucial aspect of web development that plays a significant role in enhancing the user experience. By understanding the causes of CLS and implementing effective strategies to reduce it, website owners can ensure that their visitors have a smooth and enjoyable browsing experience.

Throughout this article, we have explored the main causes of CLS, including images without dimensions, asynchronous content, and slow-loading fonts. We have also discussed various techniques to mitigate CLS, such as using aspect ratios for images, preloading resources, and optimizing web fonts.

By implementing these best practices, website owners can minimize CLS and improve their Core Web Vitals score, leading to higher search engine rankings and increased organic traffic. Not only does this benefit the website's visibility, but it also results in happier users who are more likely to spend time browsing the site and converting into customers.

To achieve these improvements, it is essential for web developers to prioritize CLS minimization in their development process. By regularly auditing websites for CLS issues, staying up to date with best practices, and monitoring performance metrics, developers can ensure that their websites provide a seamless and engaging user experience.

In conclusion, CLS minimization is not just a technical consideration but a crucial factor in the success of any website. By optimizing for CLS, website owners can enhance their search engine visibility, drive more organic traffic, and ultimately improve user satisfaction. So, let's prioritize CLS minimization to deliver a better web experience for all.

Web Design & DevelopmentPerformance Impact on Conversion RateCLS Minimization