What Core Web Vitals are
Core Web Vitals are three numbers Google measures on real-world visits to your website. Together they describe how the site feels to use:
- LCP (Largest Contentful Paint): how long it takes for the main content to appear after a click.
- INP (Interaction to Next Paint): how long it takes for the site to respond to a tap or click after it loads.
- CLS (Cumulative Layout Shift): how much the page jumps around as it loads.
Each has a "good" threshold. Sites with green scores on all three rank higher in Google than otherwise-equivalent sites with yellow or red scores.
Why Google measures them
Google's job is to send searchers to pages that satisfy their query. A page that loads slowly, doesn't respond to clicks, or jumps around as it renders is less likely to satisfy. Google measures the experience because the experience predicts whether visitors stay or bounce.
Core Web Vitals became an explicit ranking signal in 2021. Google has increased their weight steadily since.
What "good" actually means
The thresholds, on real-world mobile devices:
- LCP: under 2.5 seconds = good. 2.5–4 seconds = needs improvement. Over 4 seconds = poor.
- INP: under 200ms = good. 200–500ms = needs improvement. Over 500ms = poor.
- CLS: under 0.1 = good. 0.1–0.25 = needs improvement. Over 0.25 = poor.
Google publishes these in their PageSpeed Insights tool (pagespeed.web.dev). Type your URL in and see your scores.
Where most sites fail
In our audits of small-business sites in Alberta, the most common failure pattern:
- LCP failure: 60-70% of sites. Usually because the hero image isn't optimized or the page weight is too large.
- CLS failure: 40-50% of sites. Usually because images don't have width/height attributes, so the page reflows as they load.
- INP failure: 30-40% of sites. Usually because of heavy third-party JavaScript (chat widgets, ad scripts, builder-platform overhead).
WordPress + Elementor sites fail all three at much higher rates than custom-coded sites. Webflow sites fail at moderate rates without manual optimization. Hand-coded sites consistently pass all three when built with performance in mind.
What to do if your site is failing
Three options, in order of effort:
1. Quick wins on your existing site. Compress images, add width/height attributes to all images, defer non-critical JavaScript, enable gzip/brotli compression. A skilled developer can usually pull a site from yellow into green over 1-2 weeks for a few thousand dollars. We'll quote this kind of audit if you want one.
2. Optimize the platform. If you're on WordPress, switch to a leaner theme (Astra, GeneratePress) and remove Elementor or Divi. If you're on Webflow, audit and remove unused interactions, defer the SDK, optimize hero images. Mid-effort, mid-cost.
3. Migrate to hand-coded. The most permanent fix. Ships green Core Web Vitals by default and removes the platform overhead causing the original failures. Higher effort and cost up-front; lowest TCO over 3-5 years.
The business impact
A real example from our work. A Red Deer business came to us after their templated WordPress site had been gradually losing organic traffic for 18 months. We rebuilt the site hand-coded, ran a careful URL migration, and shipped with green Core Web Vitals on every page.
Within 6 weeks of launch, organic traffic was up 34%. Within 12 weeks, it was up 67%. The business had been losing rankings to competitors with better-performing sites; the rebuild reversed that.
This isn't a guarantee — every site's situation is different — but the pattern is consistent enough that we now consider Core Web Vitals optimization the single highest-leverage SEO investment for most small businesses.
How to test your own site
Three free tools:
- PageSpeed Insights (pagespeed.web.dev): lab + field data, both Mobile and Desktop. Start here.
- Chrome DevTools (Lighthouse tab): lab data only, but lets you test on different network throttles.
- Google Search Console (Page Experience report): real-world data from actual visitors over the past 28 days. The most accurate picture of how Google sees your site.
If you're seeing yellow or red on any of these, that's a signal worth acting on. Performance work doesn't wait — every month you stay slow, your competitors with faster sites pull ahead.