What Core Web Vitals measure, the thresholds, and what Google says about rankings

Largest Contentful Paint measures loading. For a good experience, it should happen within 2.5 seconds of the page starting to load. Interaction to Next Paint measures interactivity, and a good page has an INP of 200 milliseconds or less. Cumulative Layout Shift measures visual stability, and a good page keeps it at 0.1 or less.

Google describes each metric as covering a distinct part of the user experience. Each one can be measured in the field, from real visits rather than only from lab tests.

Google's guidance is to measure at the 75th percentile of page loads, segmented across mobile and desktop. A page passes only if it meets the recommended target for all three metrics at that percentile. Measuring at the 75th percentile means at least three quarters of page loads must meet each target, so a page fails if more than a quarter of visits miss a threshold.

Google Search Central recommends that site owners achieve good Core Web Vitals to succeed in Google Search and to give a good user experience in general. It says these and other page experience aspects match what its ranking systems look for. The page does not say how much weight they carry against other signals, so treat good scores as something Google asks for, not as a promise of a better ranking.

The Core Web Vitals report in Search Console shows how a site's pages perform. Start there before changing anything.

Google says the metrics in Core Web Vitals will change. New metrics start as experimental, move to pending, and then become stable. Pending metrics stay pending for at least six months so sites can adjust.

INP is the recent example. It was developed to cover runtime responsiveness more fully than First Input Delay. In 2023 it moved from experimental to pending with the intent to retire FID, and it is now stable alongside LCP and CLS.