Core Web Vitals are the three key metrics Google uses to measure a page's user experience: LCP (loading speed), INP (responsiveness to interaction), and CLS (visual stability). These metrics directly affect both search ranking and conversion rate. Improving them means optimizing images, reducing unnecessary JavaScript, and keeping the layout stable. Performance is at the center of our web development service.
The Three Metrics and Their Targets
- LCP (Largest Contentful Paint): time for the largest content to load — target under 2.5 seconds
- INP (Interaction to Next Paint): response time to user interaction — target under 200 ms
- CLS (Cumulative Layout Shift): unexpected layout shifts — target under 0.1
Research shows that as page load time goes from 1 second to 3 seconds, the probability of a bounce rises by about 32%. Speed translates directly into revenue.
How to Improve LCP?
- Serve images in WebP/AVIF format and at the right size
- Preload critical images and lazy load the rest
- Reduce server response time (TTFB) and use a CDN
- Reduce render-blocking CSS/JS files
How to Improve INP and CLS?
For INP, split heavy JavaScript tasks and keep the main thread free. For CLS, give images and ad slots fixed dimensions, load fonts without layout shift, and avoid pushing content up and down dynamically.
Measurement Tools
PageSpeed Insights, Lighthouse, and Google Search Console's Core Web Vitals report evaluate your pages with real-user data (CrUX). For general speed techniques, our article on website speed-up methods is a complementary resource.
Conclusion
Core Web Vitals turn user experience into concrete numbers and affect both ranking and conversion. With a modern framework using server-side rendering, automatic image optimization, and code splitting, keeping these metrics in the green zone becomes easy. For broader context, see our SEO guide.