What the three metrics measure
web.dev's Core Web Vitals overview defines three metrics and "good" thresholds, assessed at the 75th percentile of page loads:
| Metric | Measures | "Good" |
|---|---|---|
| LCP — Largest Contentful Paint | How quickly the main content appears | 2.5 seconds or less |
| INP — Interaction to Next Paint | How quickly the page responds to taps and clicks | 200 milliseconds or less |
| CLS — Cumulative Layout Shift | How much the layout jumps around while loading | 0.1 or less |
INP replaced an older metric (First Input Delay) as a Core Web Vital in 2024, so older articles may mention FID.
How to check for free
- PageSpeed Insights shows real-user (field) data when enough is available, plus a lab test.
- Search Console has a Core Web Vitals report for verified sites; see setting up Search Console.
- A real phone. Load your site on a mid-range phone over mobile data, away from your office Wi-Fi.
Field data reflects real visitors; lab scores are a simulation. When they disagree, field data is closer to what customers experience.
Fixes that usually matter on small sites
Large hero images (LCP)
The biggest element is often a hero photo. Resize it to the size actually displayed, use a modern format such as WebP or AVIF, and don't lazy-load the main above-the-fold image.
Layout jumps (CLS)
Set width and height on images, reserve space for embeds and banners, and avoid inserting content above what people are reading. Cookie banners and chat widgets are common culprits.
Heavy scripts (INP)
Every chat widget, tracking pixel, slider and plugin adds script. Remove what you don't use. Load non-essential third-party scripts after the main content.
Fonts
Limit the number of font files and weights; use font-display settings that show text promptly.
What to ignore
- Chasing 100. A lab score of 100 isn't required for a good experience. Fix the obvious problems and move on.
- Every suggestion in the report. Some are minor or not practical for your setup.
- Desktop-only testing. Mobile is where most local service visitors are.
Keep perspective
Google's page experience documentation describes page experience as one consideration among many, and makes clear that relevant, helpful content still matters most. A fast page with nothing useful on it won't help; a useful page that's slow loses people. Do both.
On MendRev sites
MendRev builds with lightweight code and no bloated page builders, and Website Pro includes a speed and accessibility pass. We don't promise a particular score; we test on real phones.
Questions
Will improving Core Web Vitals improve my rankings?
Google describes page experience as one of many signals and says great page experience doesn't override having helpful content. Improve speed mainly because it helps visitors.
My site has no field data. What do I do?
Small sites often lack enough real-user data for the public report. Use lab tests as a guide and test on a real mid-range phone over mobile data.
Sources and further reading
- web.dev's Core Web Vitals overview web.dev
- LCP web.dev
- INP web.dev
- CLS web.dev
- PageSpeed Insights pagespeed.web.dev
- page experience documentation developers.google.com
Official documentation changes. Check the current version before you rely on a rule, limit or setting.
Next step
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