Core Web Vitals

What it is

Largest Contentful Paint (LCP, ≤2.5s), Interaction to Next Paint (INP, ≤200ms), Cumulative Layout Shift (CLS, ≤0.1). Measured in field data via the Chrome User Experience Report (CrUX).

Why it matters

Google uses CWV as a ranking signal. More importantly, sites that pass CWV have lower bounce and higher conversion — the metrics correlate with revenue, not just SEO.

Who it applies to

Every public-facing site that wants Google traffic or conversions.

How WQI scores it

Web Quality Index considers this standard satisfied when any of the 2 supporting factors pass.

1 of 2 supporting factors are currently collected. Sites where the remaining 1 haven't been measured will show as partial or unknown on this standard until the data lands.

Related standards

See also

HTTP/2 , HTTP/3 , Compression

Standards that share factors with this one

Auto-computed from overlapping factor tickets in satisfiedBy, excluding standards already listed under "See also" above. Strong overlap suggests these standards rise and fall together when sites are scored.

• Interaction to Next Paint (INP) 1 shared factor Performance Replaced FID as a Core Web Vital in March 2024. Measures responsiveness across the full page lifecycle — clicks, taps, key presses — not just the first interaction. ≤200ms is the bar.
• Largest Contentful Paint (LCP) 1 shared factor Performance Time until the largest above-fold element renders — usually the hero image or H1. ≤2.5s at the 75th percentile is the `good` threshold; >4s is poor.
• Mobile viewport meta tag 1 shared factor SEO `<meta name="viewport" content="width=device-width, initial-scale=1">` — one line that decides whether your site is usable on a phone. Mobile-first indexing means without it you don't rank.
• Resource hints (preconnect / preload / prefetch / dns-prefetch) 1 shared factor Performance Tell the browser which connections, fonts, scripts, and next-pages it should warm up before they're strictly needed. Single-digit-percent LCP improvements per hint, multiplied across a page.
• Speed Index 1 shared factor Performance Average time at which visible parts of the page are displayed, computed from a frame-by-frame video of the load. Captures `feels fast` better than any single milestone metric.

Other references

• tooling Chrome User Experience Report (CrUX)
• guidance INP becomes a Core Web Vital (March 2024)
• tooling PageSpeed Insights