Core Web Vitals
Google’s standardized field metrics for real-world page experience — measured from actual Chrome users (the Chrome User Experience Report, crux, at p75 over 28 days), not lab tools.
| Metric | Measures | ”Good” |
|---|---|---|
| LCP — Largest Contentful Paint | loading | < 2.5 s |
| INP — Interaction to Next Paint | responsiveness | < 200 ms |
| CLS — Cumulative Layout Shift | visual stability | < 0.1 |
A page passes when 75% of real users hit “good” on all three. INP replaced First Input Delay (FID) in March 2024.
Why this wiki cares
- The SEO link: Core Web Vitals are a (minor) Google ranking factor — see the report core-web-vitals-seo. This is the main channel through which page-weight and performance choices touch search visibility.
- The performance link: byte weight feeds LCP, but CWV is multifactorial (delivery, JS execution, TTFB also matter) — the nuance behind the page-weight thesis in synthesis and the landing-page-14kb minimalism case. The Web Almanac shows the execution tax directly: 90th-percentile mobile Total Blocking Time = 5,786 ms (web-almanac-page-weight-2024), and only ~70% of pages even use text compression.
- The enforcement link: CWV “good” thresholds are often encoded as milestone/score targets in a performance-budget.
Cross-wiki note
The sibling static-site-wiki also maintains a core-web-vitals page, where CWV is the
yardstick for comparing static-site generators vs. CMSs (and where a “page weight is not
destiny” contradiction was adjudicated by HTTP Archive field data). Same metric, two
lenses: here it’s the SEO/perf consequence; there it’s the platform scoreboard.