Core Web Vitals are three measurements Google uses to judge how a page feels to real visitors. They are part of Google's page experience signals and directly affect whether visitors stay or leave.
The three metrics
- LCP (Largest Contentful Paint) — how fast the main content appears. Aim for under 2.5 seconds.
- INP (Interaction to Next Paint) — how quickly the page responds to taps and clicks. Aim for under 200 milliseconds.
- CLS (Cumulative Layout Shift) — how much the page jumps around while loading. Aim for 0.1 or less.
Why they matter
A slow or jumpy website frustrates people, especially on mobile data. Visitors who leave never become enquiries. Good vitals also help when Google compares pages of similar quality.
Common causes of poor scores
- Huge, uncompressed images
- Too many third-party scripts (chat widgets, trackers)
- Web fonts loading late and shifting text
- Images and ads without reserved space
- Heavy page builders and plugins
Quick wins
- Convert images to WebP or AVIF and serve the right size
- Lazy-load images below the fold
- Set width and height on images and embeds
- Self-host fonts and preload the important ones
- Remove plugins and scripts you don't use
How to check your site
Use PageSpeed Insights and the Core Web Vitals report in Google Search Console. Field data (from real users) matters more than a single lab test.
Summary
Fast, stable, responsive pages are good for visitors and good for search. Fix images and scripts first — they cause most problems.