How to Fix Largest Contentful Paint (LCP)

/ By / Speed Optimization
Fix Largest Contentful Paint (LCP)

Improving your largest contentful paint (LCP) score is crucial for delivering a smooth user experience on your website. LCP measures how long it takes for the largest image or text block to load on the initial page load. A high LCP score indicates layout shift and visual instability.

Follow these steps to diagnose and improve your site’s LCP score:

Key Takeaways:

  • Identify landing pages with poor LCP scores using Chrome DevTools or web analytics.
  • Minimize render-blocking JavaScript to allow crucial content to load first.
  • Optimize images by compressing, resizing, lazy loading, and using newer formats like AVIF.
  • Prefetch key assets to speed up page load.
  • Use skeleton screens to improve perceived performance.
  • Avoid excessive DOM size, third-party tags, and unoptimized web fonts.
  • Check for other factors like slow servers, stale caches, and bloated page weight.
Improve site speed

1. Find Pages with High LCP

The first step is identifying pages on your site with particularly high LCP scores. There are two main ways to do this:

Chrome DevTools – Open the page in Chrome and access the Performance panel. Reload the page and look for the LCP timing in the metrics. Values over 2.5 seconds are poor.

Web Analytics – Google Analytics and many other analytics tools will report LCP values. Look for high averages on key landing pages. Segments can help identify issues for mobile vs desktop.

For comparison, the ideal LCP score is under 1.8 seconds on mobile and 2.5 seconds on desktop.

Focus any optimization efforts on pages with LCP scores far exceeding those targets. Even if your overall site LCP score looks decent, individual pages may still have issues.

2. Minimize Render-Blocking Resources

Render-blocking JavaScript is one of the biggest causes of poor LCP scores. To improve it:

Defer non-critical JS – Use defer attributes to delay parsing of JS that doesn’t need to load immediately:

html

<script defer src="analytics.js"></script>

Lazy load JS – Load JS dynamically only when needed using load event listeners:

js

window.addEventListener('load', function() { const script = document.createElement('script'); script.src = 'carousel.js'; document.head.appendChild(script); });

Code splitting – Split JS bundles into smaller chunks that can load incrementally.

Minimize JS size – Minify JS using tools like Terser to decrease parse and compile time.

Every blocking JS script delays page rendering. Eliminate anything non-essential from loading immediately.

3. Optimize Images

Images often account for most of the LCP time. To streamline them:

  • Compress images – Use tools like ImageOptim or Squoosh to minimize file sizes.
  • Resize images – Scale images to the displayed size rather than downloading huge assets.
  • Lazy load offscreen images – Defer loading of images below the fold using the loading="lazy" attribute.
  • Use AVIF/WebP formats – Leverage newer image types for better compression than JPG/PNG.
  • Add image CDN – Speed up image load times by serving them from a content delivery network.
  • Inline critical images – Add small icons/logos directly in HTML rather than extra network requests.

Aim to optimize your hero images and any other large images that may impact LCP.

4. Prefetch Key Requests

Prefetching instructs the browser to silently load assets in the background before users navigate to a page.

Add prefetch links in the <head>:

html

<link rel="prefetch" href="/category-page" as="document">

Or preload key requests:

html

<link rel="preload" href="hero-image.png" as="image">

This technique accelerates page transitions and avoids lazy loading for crucial LCP elements.

5. Use Skeleton Screens

Skeleton screens display placeholder UI elements like headers, cards, and images before the full page content loads.

For example, show wireframes with gray blocks instead of actual images. This makes the page appear to load faster.

Use CSS or JavaScript to toggle skeleton screens on/off based on loading state.

6. Optimize Render-Blocking Resources

Avoid anything that blocks initial rendering in the critical rendering path:

  • Minimize DOM size, nesting depth, and complex CSS selectors.
  • Lazy load non-critical CSS or inline it.
  • Eliminate render-blocking third-party tags like analytics.
  • Use font stacks rather than custom web fonts to prevent FOIT (flash of invisible text).
  • Set optimal font loading strategies.
  • Avoid HTTP requests to other domains which requires DNS lookup.

Follow performance best practices to keep pages lean and optimized.

7. Check for Other Factors

Some other common LCP offenders include:

  • Slow server response – Upgrade hosting or use a CDN to accelerate delivery.
  • Dirty caches – Hard refresh and clear CDN caches if assets seem outdated.
  • Too many redirects – Consolidate redirects to avoid excessive round trips.
  • Huge page weight – Defer non-critical resources, compress files, and prune unnecessary bloat.

Diagnosing the root cause requires digging into the page load waterfall and resource timing metrics.

Fix First Contentful Paint

FAQ

What is a good LCP score?

For mobile, aim for under 1.8 seconds. On desktop, under 2.5 seconds is good. Pages under 1 second are perceived as extremely fast.

What is the impact of a high LCP score?

High LCP causes layout shifts of page content after loading begins. This creates visual instability and jittery UX. Users may see blank screens, flash of unstyled content, or late pop-ins of images.

Is LCP more important than Time to First Byte?

LCP specifically measures loading of crucial page content. TTFB is just the initial HTTP response from the server. LCP has a stronger correlation to real world UX.

How is LCP calculated?

LCP records the render time of the largest image or text block visible within the viewport. The exact element can vary across different device sizes.

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Can preloading improve LCP?

Yes, preloading key assets like web fonts, CSS, and images helps deliver them sooner, preventing render-blocking requests.

Conclusion

Optimizing LCP should be a top priority if you want to improve perceived load times. Focus on landing pages first before tackling site-wide problems. Assets like images and fonts are common LCP culprits, so tackle them first. But also look for less obvious issues like JavaScript bloat, uncached assets, and server delays that extend the loading sequence.

With some targeted performance tuning, you can significantly improve LCP scores and create snappier first-page load experiences. Fast loading times keep users happy and lead to better engagement and conversion rates.

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