Core Web Vitals: A Practical Guide to Better Scores

Core Web Vitals are Google's standardised user experience metrics. They became a confirmed ranking factor in 2021 and remain one of the clearest signals Google uses to evaluate page quality. Unlike most ranking factors, they are entirely measurable, entirely improvable and directly correlate with user satisfaction.

The three Core Web Vitals explained

LCP (Largest Contentful Paint): measures how quickly the largest visible element loads. Target: under 2.5 seconds. The largest element is usually a hero image or above-the-fold heading. INP (Interaction to Next Paint): replaced FID in 2024. Measures how quickly the page responds to user interactions. Target: under 200ms. CLS (Cumulative Layout Shift): measures visual stability - how much the page layout shifts during loading. Target: under 0.1. Caused by elements appearing without reserved space.

How to check your Core Web Vitals

Google Search Console: Core Web Vitals report shows field data (real user measurements) across your entire site, grouped by URL type. Google PageSpeed Insights: shows both lab data and field data for individual URLs with specific recommendations. Chrome DevTools: Lighthouse tab for local testing.

Improving LCP

Compress and convert hero images to WebP. Preload the LCP image with a link rel='preload' tag. Use a CDN for faster delivery. Remove render-blocking resources.

Improving INP

Reduce JavaScript execution time. Break up long tasks (over 50ms) into smaller chunks. Remove unused JavaScript and defer non-critical scripts.

Improving CLS

Add explicit width and height to all images and video elements. Reserve space for ads, embeds and dynamic content. Avoid inserting content above existing content.

Conclusion

Check your Core Web Vitals report in GSC today. Focus on pages marked as 'Poor' first. LCP is the most impactful metric to improve for most websites and usually has the clearest fix: optimise your hero image.