Mobile viewport meta tag

What it is

The viewport meta tag, defined in the WHATWG HTML spec and operationalized in Google's mobile-friendly criteria. Tells the browser to size the layout viewport to the device width rather than zoom out to a default 980px desktop canvas.

Why it matters

Google indexes the mobile version of every site by default (mobile-first indexing). A page that renders zoomed-out, with 4pt text and tap targets the size of a sesame seed, fails the mobile-friendly check and gets demoted. The fix is one meta tag.

Who it applies to

Every public site that wants Google traffic — which is to say, every public site.

How WQI scores it

Web Quality Index considers this standard satisfied when the supporting factor passes.

Related standards

See also

CWV , Search Essentials

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.

• 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.
• 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

• guidance Google — mobile-first indexing