Core Web Vitals Explained: Your Guide to Google's Page Experience
Core Web Vitals are three measurements Google uses to judge real-world user experience: how quickly the main content loads, how quickly the page responds to interaction, and how stable the layout is. They are a ranking signal, though a modest one; their bigger value is happier visitors.
Published by SEO Consultants · Last reviewed
The three metrics
| Metric | Measures | Good | Poor |
|---|---|---|---|
| Largest Contentful Paint (LCP) | Loading of the main content | 2.5 seconds or less | More than 4 seconds |
| Interaction to Next Paint (INP) | Responsiveness to clicks and taps | 200 milliseconds or less | More than 500 milliseconds |
| Cumulative Layout Shift (CLS) | Visual stability | 0.1 or less | More than 0.25 |
Google assesses each metric at the 75th percentile of real visits. INP replaced First Input Delay (FID) as a Core Web Vital in March 2024.
How to measure
- The Core Web Vitals report in Google Search Console groups URLs by status.
- PageSpeed Insights shows real-user data and lab diagnostics for a single page.
- Chrome DevTools and Lighthouse help developers investigate.
Common fixes
Improve LCP
Compress and correctly size images, use modern formats, preload the main image, and reduce slow server responses.
Improve INP
Reduce heavy JavaScript, break up long tasks and remove unnecessary third-party scripts.
Improve CLS
Set width and height on images and embeds, reserve space for adverts and avoid inserting content above existing content.
Need help?
Performance is part of our technical SEO services. See also the ultimate guide to technical SEO.
Related pages
- ServicesTechnical SEOTechnical SEO for UK websites: crawlability, indexing, site speed, Core Web Vitals, structured data, migrations and site architecture.
- GuidesTechnical SEO GuideA thorough guide to technical SEO: crawling, indexing, canonicals, redirects, JavaScript, site speed, structured data and site architecture.
- ServicesSEO AuditsIn-depth SEO audits covering technical health, content and links, with a prioritised action plan written in plain English.
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