Google's Core Web Vitals are three metrics that capture the user experience of loading, interactivity, and visual stability. They affect search ranking, but more importantly, they correlate with real user satisfaction. Understanding what each measures helps you fix the right problems.

LCP: Largest Contentful Paint

LCP measures when the largest visible element finishes rendering — usually a hero image or heading. Target: under 2.5 seconds. The most common fixes: preload critical images, inline critical CSS, and avoid render-blocking JavaScript. Server response time is often the hidden bottleneck.