Glossary
What are Core Web Vitals?
Core Web Vitals are three measurements Google uses to judge the real-world experience of a web page: Largest Contentful Paint (loading), Interaction to Next Paint (responsiveness) and Cumulative Layout Shift (visual stability).
Also called CWV, LCP, INP and CLS
The three metrics
- Largest Contentful Paint (LCP): how long the biggest image or text block takes to appear. Good is 2.5 seconds or less
- Interaction to Next Paint (INP): how quickly the page responds to clicks, taps and typing. Good is 200 milliseconds or less. INP replaced First Input Delay in March 2024
- Cumulative Layout Shift (CLS): how much the layout jumps around while loading. Good is 0.1 or less
Field data vs lab data
Google judges a page by field data: measurements from real Chrome users, collected in the Chrome User Experience Report. A page passes when at least 75% of visits meet the “good” threshold for each metric. Lab tools such as Lighthouse and PageSpeed Insights’ lab score simulate one load on one device; they are useful for finding problems but are not what Google uses for ranking.
Low-traffic pages may not have enough field data, in which case Google looks at data for the whole site.
Why it matters for B2B websites
Core Web Vitals are part of Google’s page experience signals. They rarely outrank relevance, but between two similar pages the faster, steadier one has an edge. The bigger effect is on people: a buyer opening your site from a LinkedIn post on a phone will not wait for a slow hero video, and a button that jumps as they tap it costs trust.
Common causes of poor scores
- Large uncompressed hero images or autoplay video
- Third-party scripts: chat widgets, tag managers, heatmaps
- Web fonts loading late and swapping
- Images and embeds without set width and height
- Heavy JavaScript running on every click
How we handle it
We size and compress images, reserve space for media, load third-party scripts late and keep JavaScript to what a page needs. After launch we watch field data in Search Console rather than chasing a lab score. Our website maintenance plans include keeping an eye on these numbers as content and scripts are added.
Last updated 15 November 2026
