LCP (Largest Contentful Paint)

LCP (Largest Contentful Paint) is one of the three main Core Web Vitals metrics developed by Google. It measures how long it takes for the largest element of a page — most often a large image, a banner or the main text block — to be fully rendered within the visible area of the browser window. LCP answers a simple user question: "how quickly do I see what I came for?"

How LCP is measured

The browser continuously tracks which visible element occupies the largest area and records the moment it is displayed. An LCP under 2.5 seconds is considered good, from 2.5 to 4 seconds needs improvement, and above 4 seconds is poor. The usual candidates for the "largest element" are:

• images and background images in the header section;
• video elements with a visible thumbnail;
• large blocks of text, such as an article's H1 heading.

The result is made up of several phases: server response time (TTFB), resource load delay, the time to download it and the time to render it.

Practical application

Because LCP is a Google ranking factor, optimizing it directly affects SEO and conversion. The most effective actions are: reducing TTFB through faster hosting and caching, delivering resources from a CDN, compressing and correctly sizing images (WebP/AVIF formats), eliminating render-blocking resources and prioritizing the download of the main graphic. The metric is monitored in Google Search Console, PageSpeed Insights and Lighthouse.

When analyzing LCP, it is important to distinguish lab data from field data. Lab tests are run under controlled conditions and are excellent for diagnosis during development, whereas rankings are decided by data from real users, spanning different devices and connection qualities. That is why an LCP improvement should be verified over the course of weeks by watching the Search Console report. Particular attention belongs to the mobile version, where weaker processors and slower networks most often push the metric past the 2.5-second threshold.