A Guide to LCP Optimisation

Improving SEO with Optimised LCP


When it comes to website performance, Google's Core Web Vitals are becoming a crucial factor. Among these vitals, the Largest Contentful Paint (LCP) plays a pivotal role in user experience and SEO. This blog post provides a comprehensive understanding of LCP and offers some valuable optimisation strategies.


What is LCP? Largest Contentful Paint (LCP) is a user-centric metric for measuring perceived load speed. It marks the point during page load when the main content is likely to have been fully rendered on the screen. High LCP values may indicate slow load times and can be frustrating for users.



gtmetrix full results





How and Where to Check LCP

LCP values can be checked using various tools including GTMetrix and Lighthouse. For Chrome users, there's a Core Web Vitals plugin. You can access it by pressing ctrl + shift + p and then typing 'web vitals overlay' in the command menu and selecting it.


chrome web vitals image  web vitals instructions


However, the most significant tool to gauge LCP values is the Google Search Console. It provides real-world usage data which is the most accurate. Yet, it's important to note that these vitals may not show in the Google Search Console unless your website receives a significant amount of traffic.


Potential LCP Inflators: Surprisingly, web fonts can significantly inflate your LCP. These fonts can delay text rendering and push back the LCP. Additionally, unused CSS or scripts on the current page can negatively impact your LCP score. It's essential to identify and remove these elements to improve load times.


Key Optimisation Strategies for Improving LCP


Optimisation Tips:


  • Organise CSS: To minimise rendering delays, place the CSS responsible for the top of the page in the head section. This way, the browser doesn't need to download the entire CSS file before rendering the main content.


  • Utilise defer and async: Using the 'defer' and 'async' attributes for scripts can help improve load times. The 'async' attribute allows scripts to execute as soon as they're downloaded, without waiting for other elements. 'Defer' is used for non-critical scripts, allowing the browser to continue parsing the page.


  • Image Optimisation: The size and format of images can significantly impact your LCP. Opt for modern formats like WebP or AVIF for superior compression and quality characteristics compared to older formats. Tools like Photopea.com can help with image format conversions.


  • Compression and Server Caching: Compressing your CSS and JS files on the server, particularly if you're using IIS, can drastically improve your LCP. This process minimises the file size, allowing for faster download and parsing times. Alongside compression, implementing server caching can further speed up your site by storing a version of your web page, reducing the need to fully reload it with every visit.


Remember to check compatibility across different browsers when using newer image formats. Websites like 'caniuse.com' can provide insights into what is supported on each browser.





Paying attention to LCP and other Core Web Vitals is no longer an option but a necessity in the quest for better user experience and improved SEO. With these tips, you can optimise your website's LCP, resulting in faster load times and a smoother user experience. As always, it's essential to keep testing and tweaking, as what works best can vary from site to site.




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