Core Web Vitals
Three Google metrics that measure how fast a page loads, how quickly it responds and whether its content jumps about.
Glossary · SEO & AI search
Core Web Vitals are metrics defined by Google to assess what real visitors experience. LCP measures how long the largest visible element of a page takes to appear, INP how quickly the page reacts to a tap or click, and CLS how much the content shifts while loading.
They are calculated from real browsers, so they also depend on visitors’ devices and connections. A lab test on a fast computer can show a good result that phone users never experience.
Google uses these metrics as one ranking signal among many, not a decisive one. They matter more for another reason: a slow, jumpy site simply loses visitors.