The three metrics and their thresholds
A page passes when 75% of visits, measured separately on mobile and desktop, meet these thresholds:
- LCP (Largest Contentful Paint): 2.5 seconds or less. Above 4 seconds is rated poor.
- INP (Interaction to Next Paint): 200 milliseconds or less. Above 500 ms is rated poor.
- CLS (Cumulative Layout Shift): 0.1 or less. Above 0.25 is rated poor.
Field data vs. lab data
Field data comes from the Chrome User Experience Report (CrUX) and feeds both the Core Web Vitals report in Search Console and the top section of PageSpeed Insights. That is the data Google cares about. Lab data, produced by a single Lighthouse run, is for debugging and can differ widely from real-world experience. Low-traffic sites may have no field data for individual pages, in which case Google looks at groups of similar pages or the whole origin.
How much they weigh in rankings
Google says good Core Web Vitals, along with other page experience aspects, align with what its core ranking systems seek to reward, without making them decisive. Relevance comes first: a fast page that misses the point will not outrank a slower page that answers the query perfectly. The most tangible payoff is often conversion, since every extra second of waiting on a phone sends visitors back to the results.
Where to start
Fix issues at the template level, not URL by URL: one change to your product page template fixes hundreds of pages at once. The biggest wins usually come from oversized hero images (LCP), third-party scripts such as chat widgets and ad tags (INP), and images or banners without reserved dimensions (CLS).