The Largest Contentful Paint (LCP) metric looks at the loading performance of your page. LCP measures the time it takes to get the largest element on the page visible within the viewport. This could be a large text block, video, or image that takes up the primary real estate on the page.
Note: This is not First Contentful Paint (FCP), which measures the time from when the page begins to load to when the first element is rendered on screen.
As the DOM is rendered, the largest element on the page may change. The Largest Contentful Paint doesn't stop counting until the largest image or element is seen on-screen.
What does Largest Contentful Paint (LCP) measure?