What the three metrics actually measure
Largest Contentful Paint (LCP) measures how long the main content takes to load. Interaction to Next Paint (INP) measures how responsive the page feels when someone clicks or taps. Cumulative Layout Shift (CLS) measures how much elements jump around as the page loads — think of a button moving just as you go to tap it.
Where to check your scores
Google's PageSpeed Insights (pagespeed.web.dev) is the fastest way to check a single page — it gives you both lab data and real-world field data from actual Australian visitors if your site has enough traffic. For a site-wide view, the Core Web Vitals report inside Google Search Console groups every URL by pass, needs improvement, or fail.
Understanding the results
Field data (real visitors) matters more than lab data for rankings, but lab data is more useful for diagnosing exactly what's slow. If PageSpeed Insights flags large images, render-blocking scripts, or unused CSS, those are your starting points — they're usually the biggest wins for the least effort.
Common causes on Australian small business sites
Uncompressed hero images, third-party scripts (chat widgets, booking plugins, tracking pixels), and web fonts loading late are the most frequent culprits. Page builders and heavy WordPress themes are also common offenders, since they load far more code than a page actually needs.
Fixing what you find
Compress and resize images before uploading, defer non-essential scripts, and set explicit width and height on images and embeds to prevent layout shift. If your host is on shared, budget hosting, that's often the ceiling you can't optimise past — upgrading hosting can outperform months of code tweaks.
Key Takeaways
- Core Web Vitals measure loading (LCP), responsiveness (INP), and stability (CLS)
- Check individual pages with PageSpeed Insights, whole-site trends in Search Console
- Field data from real visitors matters more than lab data for rankings
- Images and third-party scripts are the most common causes of poor scores
- Hosting quality sets a ceiling on how much you can improve