Largest Contentful Paint (LCP) is one of the three Core Web Vitals that Google developers created to measure the most important aspects of a user’s online experience. Simply put, LCP measures how long it takes for the largest piece of content to load and become visible on a site user’s screen. This can help retailers understand what their customers experience when they interact with their site, and it makes it easier to find areas where the LCP metric can be improved.
Why LCP Matters
The LCP score of a page essentially shows how long it takes for a web page’s main content to load fully for the visitor. A fast LCP can keep people on the site longer because it can quickly and continually provide quality content without making the person wait for several seconds. Site speed is essential for all online sellers, especially when it comes to the checkout process and product pages.
How to Calculate LCP
Site owners can access the following free tools that can measure LCP:
- PageSpeed Insights: Simply enter the URL of a web page, and PageSpeed Insights will analyze the page’s content and offer suggestions to improve the LCP metric.
- Core Web Vitals report: The Core Web Vitals report measures all three of Google’s essential metrics: LCP, FID, and CLS. Just enter a URL and see where your website stands compared to the recommended scores.
- Lighthouse: Lighthouse is an open-source, automated tool that can be run on any web page. It has options to run audits on site performance, accessibility, PWAs, SEO, and more.
Once you’ve run the tests of your choosing, here’s what your LCP score means:
- Good: 2.5 seconds or fewer
- Needs improvement: Between 2.5 and 4 seconds
- Poor: More than 4 seconds
Causes of Poor LCP
Not sure why your website’s LCP isn’t faster? The most common causes of a poor LCP score include:
- Slow server response times
- Slow resource load times
- Client-side rendering
Fixing your LCP may be as simple as optimizing your product images to allow pages to load faster, or there might be a deeper underlying issue with your site. To learn more about optimizing your LCP score, web.dev’s in-depth article is an excellent, beginner-friendly resource!