Core Web Vitals

Core Web Vitals are a set of metrics Google uses to measure how a page feels in real use: how fast the main content loads, how quickly it responds to input, and whether the layout stays stable while loading.

The current core set focuses on LCP (Largest Contentful Paint — loading), INP (Interaction to Next Paint — responsiveness), and CLS (Cumulative Layout Shift — visual stability). They are part of broader page experience signals and matter for both SEO and UX: slow or jumpy pages lose visitors and conversions.

A real-life example of Core Web Vitals

You open a store page; the big product image takes forever (poor LCP), the “Add to cart” button doesn’t react when you tap (poor INP), and the layout jumps so you click the wrong thing (poor CLS). You leave. Fixing images, scripts, hosting, and often a CDN for static assets improves those scores.

Good Core Web Vitals don’t replace useful content or clear web architecture, but they remove friction. For practical performance work, start with Improve Site Performance.