Core Web Vitals were introduced by Google as user-experience signals in ranking. They are measured in the field from Chrome User Experience Report data, not from lab tests.
The three metrics
- LCP (Largest Contentful Paint) — should be under 2.5 seconds.
- INP (Interaction to Next Paint) — should be under 200 milliseconds.
- CLS (Cumulative Layout Shift) — should be under 0.1.
Example
A homepage with an unoptimised hero image can log an LCP above four seconds on mid-range mobile, which pushes the URL out of the "Good" bucket and hurts its ranking on competitive queries.
How SEM Optimiser reports it
CWV field data is imported per URL and rolled up per template so systemic issues (for example, a shared hero component causing LCP regressions) become visible.
Related terms
- LCP (Largest Contentful Paint)
Largest Contentful Paint is the time from navigation start until the largest visible element in the viewport has been rendered, and should be under 2.5 seconds.
- INP (Interaction to Next Paint)
Interaction to Next Paint measures how quickly a page responds to a user's interactions across the whole session, and should be under 200 milliseconds.
- CLS (Cumulative Layout Shift)
Cumulative Layout Shift measures how much the visible layout of a page moves unexpectedly during load, and should be under 0.1.
- On-page SEO
On-page SEO is the practice of optimising individual web pages so their content and HTML signals match what search engines expect for the queries they target.