The Largest Contentful Paint (LCP) measures the loading time required to display the largest file or content on a page. This might include a visible image, video, web text or an H1 title.
The LCP relates to all content above the fold, but the final LCP score is only determined when the full page has loaded. A good LCP score is around 2.5 seconds. A page with an LCP score of 4 seconds or higher is considered a slow page.
LCP is one part of the three Google Core Web Vitals. The other two are First Input Delay and Cumulative Layout Shift.