Core Web Vitals are three Google metrics that measure how fast a page loads its main content (LCP), how quickly it responds to interaction (INP) and how stable the layout is while loading (CLS). They are part of Google’s page experience signals, and more importantly, they reflect whether visitors can use your site without frustration.
The three Core Web Vitals and their thresholds
| Metric | What it measures | Good | Poor |
|---|---|---|---|
| LCP (Largest Contentful Paint) | How long the main content takes to appear | 2.5 seconds or less | More than 4 seconds |
| INP (Interaction to Next Paint) | How quickly the page responds to clicks and taps | 200 milliseconds or less | More than 500 milliseconds |
| CLS (Cumulative Layout Shift) | How much the layout jumps while loading | 0.1 or less | More than 0.25 |
Google assesses these at the 75th percentile of real visits, so a page passes when most visitors get a good experience, not only those on fast connections. INP replaced the older First Input Delay (FID) metric in March 2024.
How to check your Core Web Vitals
- PageSpeed Insights shows real-user data (when available) and lab tests for a single URL
- Google Search Console has a Core Web Vitals report grouping pages across your site
- Chrome DevTools Lighthouse helps diagnose issues while you work on them
Field data from real users is what Google uses. Lab scores are useful for testing fixes but can differ from what visitors experience.
Common causes and fixes
Slow LCP
- Large, uncompressed hero images: resize and compress them, and serve modern formats such as WebP
- Slow hosting or no caching: use good hosting and a caching plugin or CDN
- Render-blocking CSS and JavaScript: remove unused plugins and defer non-critical scripts
- Lazy-loading the main image: do not lazy-load the image that appears first on screen
Poor INP
- Heavy JavaScript from page builders, sliders and third-party widgets
- Too many tracking scripts running at once
- Chat widgets and pop-ups loading immediately instead of on demand
High CLS
- Images and embeds without width and height set
- Web fonts that swap in late and change text size
- Banners, cookie notices or ads inserted above existing content
Do Core Web Vitals affect rankings?
They are a ranking signal, but relevance and content quality matter more. A fast page with weak content will not outrank a slower page that answers the query much better. The bigger benefit is usually conversions: a site that loads quickly and responds smoothly keeps more visitors long enough to call or enquire.
Where to start
Fix the pages that matter most first: your homepage, main service pages and contact page. Start with images and unused plugins, since they are the most common problems on small business WordPress sites, then re-test.
For a full review, see my Technical SEO Audit service or the technical SEO checklist for small business websites.
Put this into practice
An SEO audit measures your Core Web Vitals alongside indexing, content and local signals, and call tracking and conversion optimization shows whether faster pages are turning into more enquiries.
Written by Nazmus Shafayat, a local SEO strategist who helps accountants, dentists and trades businesses in the USA, Australia, the UK and the UAE win more calls from Google and AI search. Browse more local SEO guides.
Core Web Vitals FAQs
What is a good Core Web Vitals score?
Google considers LCP of 2.5 seconds or less, INP of 200 milliseconds or less and CLS of 0.1 or less to be good, measured at the 75th percentile of real visits.
Why is my PageSpeed score different every time?
Lab tests run in simulated conditions that vary slightly between runs. Focus on the real-user field data and on trends over time rather than a single score.
Do I need a perfect 100 score?
No. The goal is to pass the Core Web Vitals thresholds for real visitors. Chasing a perfect lab score often costs time with little benefit.
Need help with this?
I help service businesses in Australia, the UK and the USA with local SEO, Google Maps visibility and AI search optimization.