LCP (largest contentful paint) is one of the Core Web Vitals that denotes the perceived load speed. It measures the loading time of your website from the user’s perspective. To be more precise, this user-centric web performance metric determines how long your website takes in loading the largest of all elements in the viewport – an image, text or graphics found in the main content above the fold.   

LCP is vital when it comes to page loading performance. Google uses this metric to evaluate the web page experiences. 

Largest Contentful Paint - LCP

In this article, you will learn about LCP, how it works and influences search engine optimization and how to measure and optimize it for improved user experience.  

What is LCP ? 

A slow website is your Google Rankings killer. You cannot bear the loss it may cause just because the site is bouncing back the potential customers. 

Why is this so? Your website might be having a poor LCP score. 

LCP Score Range : 

Google suggests that websites should aim to maintain their LCP score within 2.5 seconds – filling the first frame of the main content above the first fold to provide a good user experience.

Good

Needs Improvement

Poor

≤ 2.5 seconds

2.5-4.0 seconds

≥ 4.0 seconds

Good LCP Score :

Good LCP Score

Performance result of bbc.com using WebPage Test

Poor LCP Score :

Poor LCP Score

Performance result of theguardian.com using WebPage Test

 FCP vs LCP :

Whenever you visit a website you will notice that all elements do not appear altogether – some appear quickly while others take longer than expected to appear on the screen.  

LCP (largest contentful paint) denotes the duration of the largest element above-the-fold page to appear on the screen. Conversely, FCP (first contentful paint) as the name implies is the duration that the first element (also called first paint) takes to appear in the viewport.  

FCP vs LCP

Ideally, both FCP and LCP should be identical. Well, LCP should be kept as low as possible. 

LCP Affecting SEO : 

LCP is a ranking signal that Google considers to determine the SERP position of your website(s). It measures the page load speed and thereby directly affects the user experience.

A better experience, convincing the users to stay on your website, decreases the bounce rate and hence improves its search engine page rankings. 

LCP measurements will give your SEO team a quick way to determine whether a blank or content-rich page will greet them. A complete piece of content should appear as soon as possible. And, this is only possible when you maintain the lowest LCP.    

Elements Triggering LCP  

According to Google, the following elements can cause LCP. 

  • Image Elements: 
      • <img> elements
      • <img> within <svg> element
      • Background images (loaded via url() function) 
    • Video Elements:
      • Thumbnail <video> (poster images)  
  • Text Elements: 
  • Complex text blocks (e.g. <h1>, <p>, <div>, and <address>, etc.)

Note: Currently, Google considers image elements only. <svg> and <video> elements are the things of the future. 

What Causes LCP ? 

  • Slow server response time 
  • Render-blocking JS & CSS 
  • Slow resource load times.
  • Client-side rendering 

Tools to Measure LCP : 

Lab Tools 

Field Tools 

How to Optimize Largest Contentful Paint ?
Generally, the following 5 optimization categories help improve the LCP metric for most of the websites:

  • Image Optimization:
  • Select the right image format 
  • Use accurate image dimensions 
  • Compress images for quick loading
  • Improved Server Performance:
  • Server optimization
  • Upgrading the hosting plan
  • Using a CDN (content delivery network)
  • CSS and JS optimization:  
  • Minifying and compressing of code files
  • Delivering smaller JS payloads
  • Implementing the critical CS
  • Preloading & Pre-Connecting:
    In this technique, you can use rel=preload, rel=preconnect, and rel=dns-prefetch to point the browser to connections and resources it needs to prioritize.
  • Client-Side Rendering Optimization:
    It depends on the target site’s setup. Be aware of the amount of work you are putting on the client and how it will affect the performance. 

For more details about LCP optimization, check out Google’s Guide

Conclusion: 

Largest Contentful Paint is a user-centric web performance metric used to determine the loading speed of a web page. It measures the duration the page’s largest element appears on the screen. Your site’s LCP score should be 2.5 sec or less to achieve good search engine page rankings. Find the LCP related issues on your site and fix them to boost page load speed and thereby, SEO. Aim for super-fast, lightweight, and fully optimized elements for smooth loading web pages, resulting in a good LCP score.   

ArhamSoft (Pvt) Ltd. is an ISO-certified custom software development company that helps businesses protect and improve their website’s search ranking signals by fixing all design- and development-related LCP issues.