High impact · weight 8 · worth up to 3.4 points of the total score
The Chrome UX Report measures Core Web Vitals on real Chrome users over the last 28 days, and it is the data Google's ranking uses, not the lab run. It exists only for pages, or whole sites, with enough traffic; when only the site has data, that is what this shows.
Fix whichever of LCP, INP and CLS is outside the good band below. Field data moves slowly: a fix shows up over the following four weeks.
Check a page for this, and the other 70 checks at once
Largest Contentful Paint
LCP is the moment the biggest element in the viewport finishes rendering, which is when a visitor feels the page has arrived. Google's threshold for good is 2.5 seconds.
Cumulative Layout Shift
CLS measures content jumping around after it appears. It is why a visitor taps the wrong button when an ad or a late-loading image pushes the page down under their finger.
Interaction to Next Paint
INP is how long the page takes to visibly respond after a tap or a click. Above 200ms the interface starts to feel like it is ignoring the user.
HTML is compressed in transit
Gzip or Brotli typically cuts HTML to a quarter of its size. Serving it uncompressed wastes that bandwidth on every single request, and it is usually one line of server config.
