What is Largest Contentful Paint

You've clicked on a webpage. The header and some text load, but you're still waiting for that main banner image or the headline to appear before the page feels truly "loaded." That moment when the most important piece of content finally shows up is what Largest Contentful Paint is all about. Nailing this metric is key to making your site feel fast and useful to your visitors.

What is Largest Contentful Paint (LCP)?

Imagine you're reading a newspaper. The Largest Contentful Paint (LCP) is the time it takes for the main headline and its feature image to appear on the page. It’s not the whole paper, but it's the biggest, most important part you see first, letting you know what the story is about.

On a website, LCP measures the time it takes for the largest visible content element—usually a hero image, a video, or a large block of text—to load within the user's screen.

Essentially, LCP answers the question: "When can the user see the most significant content on this page?" A fast LCP signals that your page is useful and ready to go.

Common Causes of a Slow Largest Contentful Paint and How to Fix Them

A slow LCP makes your page feel sluggish and incomplete. Here are the most common culprits and how you can get them sorted.

1. Large, Unoptimised Images or Videos

What it is: This is the number one cause of slow LCP. If your main content element is a huge, high-resolution image or video file, the browser has to download that massive file before it can display it.

How to fix it:

Compress Your Images: Use tools to significantly reduce the file size of your images without a noticeable drop in quality.

Use Modern Formats: Image formats like WebP or AVIF offer better compression than older formats like JPEG and PNG, meaning they load much faster.

Resize Images Correctly: Don't use a giant 4000-pixel wide image in a space that's only 800 pixels wide. Serve images that are appropriately sized for where they will be displayed.

2. Slow Server Response Time

What it is: This is the time it takes for your server to even begin sending the website files to the user's browser. If your server is slow to start, everything else will be delayed.

How to fix it:

Upgrade Your Hosting: A better-quality web host can dramatically reduce server response times.

Use a Content Delivery Network (CDN): A CDN stores copies of your site's files on servers across the globe, delivering them from a location physically closer to your user, which speeds up the initial load time.

3. Render-Blocking Code (CSS & JavaScript)

What it is: Before the browser can display your main content, it often has to stop and process large instruction files (CSS for styles, JavaScript for interactivity). If these files block the loading process, your main image or text can't be shown.

How to fix it:

Defer Non-Critical Code: Your developers can instruct the browser to load less important code (like for widgets or animations further down the page) after the main content has already been displayed.

4. Slow-Loading Web Fonts

What it is: Sometimes, the LCP element is a large headline. If that headline uses a custom font, the browser can't show the text until it has downloaded the font file, which can cause a visible delay.

How to fix it:

Optimise Font Loading: There are techniques developers can use to preload important font files or to initially display text in a standard "system font" so the user can start reading immediately while the custom font loads in the background.

Why Largest Contentful Paint Matters 📈

LCP is arguably the most important metric for measuring how fast a user perceives your page to be. It's a key part of Google's Core Web Vitals.

User Experience: A fast LCP reassures users that the page is loading correctly and that the content they came for is on its way. This reduces the likelihood that they will become impatient and leave your site (i.e., it lowers your bounce rate).

Search Engine Optimization (SEO): Google uses LCP as a significant ranking factor. A better LCP score can directly improve your website's position in search results, leading to more traffic.

Business Impact: A page that feels fast is a page that users trust. A good LCP score is correlated with better user engagement and higher conversion rates because it provides a smooth, professional-feeling experience.