Core Web Vitals

Core Web Vitals are the three metrics Google uses to judge how a page feels in practice: how quickly the main content loads, how quickly the page responds to input, and how stable the layout stays while loading. The measurements come from real Chrome users and count as a signal in Google's rankings.

• LCP (Largest Contentful Paint): the time until the largest element in the viewport has loaded, typically a hero image or a headline. Target: under 2.5 seconds.
• INP (Interaction to Next Paint): how quickly the page responds when a user clicks or types, measured across the whole visit. INP replaced the older FID metric in 2024. Target: under 200 milliseconds.
• CLS (Cumulative Layout Shift): how much the content moves while the page loads, like a button jumping just as someone reaches for it. Target: under 0.1.

The numbers live in Google Search Console and in PageSpeed Insights. Field data from real users is what counts in rankings, while lab numbers only show what a test machine experienced in a single visit. The usual culprits behind poor scores are heavy images, slow server response and blocking JavaScript.

As a ranking signal Core Web Vitals weigh modestly next to content and links, so good numbers rarely decide a first place on their own. In SEO they work as a foundation the rest of the effort stands on, and the guide to Core Web Vitals takes the three metrics one at a time.