The display time of the main content of a web page, called Largest Contentful Paint (LCP), represents one of the major indicators of Google’s Core Web Vitals.
It measures the time it takes to display the largest visible element on a page, reflecting the user’s perceived speed. In practice, Google analyzes the loading of the largest content on your page: images, videos, and large blocks of text. A good LCP is less than 2.5 seconds.
To improve your LCP and gain SEO performance, three technical levers are available to you: server optimization, reduction of blocking scripts and optimal processing of your media.
What are the main causes of a bad LCP?
A poor Largest Contentful Paint (LCP) can result from several factors:
- Long server response times delay content delivery. Optimizing your server and using a CDN can help reduce this delay.
- JavaScript and CSS scripts can block rendering, slowing down LCP. Minifying and deferring non-critical CSS, as well as reducing blocking JavaScript, are key steps.
- Slow-loading resources, especially unoptimized images, also affect LCP. Compressing images and preloading critical resources improves this.
- Client-side rendering can also be a cause, as it requires the browser to download and execute JavaScript to display the content.
How does LCP affect your site’s SEO?
Largest Contentful Paint (LCP) is a significant SEO metric. By directly influencing user experience, it impacts a website’s position in Google search results. A good LCP, less than 2.5 seconds , promotes better rankings. On the other hand, a slow LCP can lead to an increased bounce rate, where users quickly leave the site, thus harming its SEO.
In concrete terms, a poor LCP can decrease time spent on the site and reduce conversions, whether sales or registrations. On the other hand, optimizing the LCP improves user engagement and retention, thus increasing organic traffic.
Reducing load times helps ensure a smooth and satisfying user experience, which is beneficial for your SEO and your users.
What techniques can improve LCP?
To improve Largest Contentful Paint (LCP), several techniques can be implemented:
- Using a Content Delivery Network (CDN) helps reduce loading time by distributing content through servers close to the user.
- Optimizing images plays a key role: this includes proper sizing, using modern formats like WebP, and compressing files.
- Caching, both server-side and browser-side, helps speed up rendering.
- Minifying and deferring the loading of JavaScript and CSS scripts helps avoid render-blocking.
- The choice of hosting provider directly influences the reduction of loading times.
What is the impact of JavaScript and CSS scripts on LCP?
JavaScript and CSS have a significant impact on Largest Contentful Paint (LCP) . When a browser loads a page, it must parse the HTML and stops if it encounters synchronous CSS or JavaScript files. These elements block rendering, delaying the display of the main content. Therefore, minimize these blocks to optimize your LCP.
Here are some effective strategies:
- Minify CSS and JavaScript files: Remove unnecessary spaces and comments to reduce their size.
- Defer script loading: Load non-essential scripts after initial rendering using attributes like or.
asyncdefer - Inlining critical CSS: Integrate styles needed for initial display directly into the HTML.
What are the recommended tools for optimizing LCP?
Want to improve your LCP? Here are the best tools to help you do just that. Google’s PageSpeed Insights remains a must-have, offering detailed analysis and personalized recommendations.
With GTmetrix , analyze your performance in detail and receive practical advice to boost your LCP. The WebPageTest tool offers the ability to simulate tests from different locations and on various browsers, providing an accurate measurement of LCP.
On the media optimization side, tools like TinyPNG and Imagify help compress images, which is often responsible for poor LCP.
To go further, rely on a content delivery network (CDN) which will significantly reduce your loading times, while caching solutions, like WP Rocket, improve display speed.
Combining these tools will give you all the leverage you need to propel your LCP to excellence. The key? Satisfied visitors and higher rankings in search results.
How do images and other resources affect Largest Contentful Paint?
Images and other resources weigh heavily on your page load times. Without optimization, they can literally drain your LCP. Here are several technical solutions to lighten the load:
- Image optimization: Adopt formats like WebP, which reduce file size while maintaining quality. Specifically, WebP compresses your images up to 34% more than JPEG.
- Lazy loading: Load images only when they are visible on screen, reducing initial load time and improving LCP.
- Preload critical resources: Use directives like to tell the browser which resources take priority.
<link rel="preload">
These optimizations allow you to reduce your LCP by 20%.
