What Core Web Vitals measure
Core Web Vitals are three metrics Google uses to describe how a page feels to real visitors. Largest Contentful Paint (LCP) measures loading: how long until the main content appears. Interaction to Next Paint (INP) measures responsiveness: how quickly the page reacts when someone taps or clicks. Cumulative Layout Shift (CLS) measures stability: whether content jumps around while loading.
Google's 'good' thresholds are an LCP under 2.5 seconds, INP under 200 milliseconds and CLS under 0.1, measured at the 75th percentile of real visits.
Why they matter for your business
Core Web Vitals are part of Google's page experience signals, but the bigger reason to care is people. Slow, jumpy pages lose visitors before they read your offer. Faster pages generally see lower bounce rates and higher conversion rates, especially on mobile connections.
Treat speed as a feature of your product, not a technical afterthought.
The fixes with the biggest impact
- Optimise the hero image. Serve WebP or AVIF, size it correctly and preload it so it isn't discovered late.
- Reduce JavaScript. Remove unused plugins and third-party tags; defer anything that isn't needed for the first view.
- Reserve space. Set width and height on images, embeds and ads to prevent layout shifts.
- Load fonts carefully. Use font-display: swap, preload the main font and limit weights.
- Use caching and a CDN. Fast server response underpins every other metric.
How to measure progress
Use PageSpeed Insights for a quick view of both lab and field data, Search Console's Core Web Vitals report for site-wide trends, and Lighthouse in Chrome DevTools when debugging individual pages. Remember that field data updates over a rolling 28-day window, so improvements take a few weeks to show.
