How to Measure and Optimize Largest Contentful Paint for Superior UX

  • Date Published
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This article explains what Largest Contentful Paint (LCP) is, how to measure and optimize it for the best user experience.

When it comes to online success, there are many ways to go about it. An optimized user experience is one such way. Google will use different user experiences and related metrics to rank websites for SEO. It has continued to produce multiple tools to improve web performance. We’ll take a look at some of the ways in which Google is looking to improve the user experience below.

What is Google Core Web Vitals?

In its recent attempt at modifying the measure and understanding of what qualifies as decent user experience, Google regulated the page’s metrics. These standardized metrics are referred to as core web vitals and facilitate the ratings of the real-world user expertise on your website.

What is Largest Contentful Paint?

To start with, let’s look at Largest Contentful Paint (LCP). It is one of the core web vitals metrics. It measures the loading time of the biggest content component within the viewport as it becomes visible. Alternative metrics like TTFB and First Contentful Paint conjointly facilitate the live page experience, they are not present once the page has become “meaningful” for the user.

Usually, unless the most important component on the page becomes fully visible, the page might not offer sufficient context for the user. LCP is, therefore, representative of the user’s expectations. As a core web vitals metric, LCP accounts for twenty-five percent of the Performance Score, which is why it is one of the most important metrics to optimize.

Checking Your LCP Time

As per Google, the categories of parts thought of for Largest Contentful Paint are:

  • <img> elements
  • <image> elements inside an <svg> element
  • <video> elements (poster image used)
  • An element with a background image loaded via the URL function
  • Block-level elements comprising of text nodes and/or other inline-level text elements

How is LCP Measured?

Of course, there are multiple ways of measuring the LCP of your web page. The easiest way in which to do it is by using one of the platforms available that includes Lighthouse, PageSpeed Insights, Search Console as well as Chrome User Experience Report. For example, Google PageSpeed Insights in its report indicates the component for calculating the LCP.

What is a Good LCP?

To provide decent user expertise, you must attempt to maintain an LCP of 2.5 seconds or lower on your site. A majority of your page loads ought to be happening below this threshold. Now that we all know what LCPs are and what our target ought to be let’s examine ways in which to enhance LCP.

(Please add the image named Majority of pages must load at an LCP of 2.5 seconds or lower.jpg)

How to optimize Largest Contentful Paint (LCP)

The underlying system of reducing LCP altogether is to cut back on the data downloaded onto the user’s device and reduce the time it takes to manage that content and ensure seamless user experience.

Optimize your pictures

On most sites, the above-the-fold content typically contains an oversized image that is required for LCP. It might be a hero image, a carousel, or a banner. You must optimize these pictures for a more robust LCP.

To optimize your pictures, you must use a third-party image CDN like The advantage of employing a third-party image CDN is that you simply target your actual business and leave image optimization to the image CDN.

Real-time transformations for responsive pictures

Google uses mobile-first compartmentalization for nearly all sites. This is why it is necessary to optimize LCP for mobile over desktop. Each image must be scaled right down to as per the layout’s demand.

For example, you would like the image in a smaller size on the listing page and a bigger size on the product detail page. This resizing ensures that you don’t seem to be using any extra bytes than what’s needed for that exact page.

Cache pictures and improve delivery time

Image CDNs use Content Delivery Network (CDN) to deliver the photographs. Employing a CDN ensures that pictures load from a nearby location rather than a server that may well be halfway across the world.

Preload essential resources

There are instances where the browser might not load a visual if it impacts LCP. As an example, a banner image on top of the fold may be seen as a background image within a CSS file. Since the browser would not know this about the image until the CSS file is downloaded, it’ll not load it.

Now, if you’re asking, “How do I preload the largest Contentful paint image?”, the answer is simple. You’ll be able to preload them by using a tag with a rel= “preload” attribute to the top section of your hypertext mark-up language document.

While you’ll be able to preload multiple resources in a document, you must limit it to above-the-fold pictures or videos, page-wide font files, or essential CSS and JS files.

Reduce server response times

If your server takes longer to load than what is deemed normal, then the time it takes to load the page on the screen goes up. It negatively affects each page speed metric, together with LCP. To enhance your server response times, you can:

  • Analyze and optimize your servers
  • Use a Content Delivery Network
  • Preconnect to third-party origins
  • Serve content cache-first with a service worker
  • Compress text files

Improve client device response times

If your page takes long to load, it can be off-putting to potential customers. Luckily, there are a few things you can do to ensure that it loads properly on their end and creates a seamless user experience. This includes:

  • Inlining essential CSS
  • Minifying and press the content
  • Optimizing LCP for client-side rendering
  • Using server-side rendering
  • Using pre-rendering

LCP has become a big search ranking factor that powerfully correlates with the user experience and journey. Therefore, if you run a web business, you must optimize these components to ensure the success of the endeavor.

Author Bio

Ghia Marnewick is a writer, social media manager and digital manager. She writes content for Aumcore and is passionate about finding new ways of sharing information with the world.