Index coverage (Page indexing)

Index coverage is the record of which URLs a search engine has indexed and, for the ones it hasn’t, why not. Google reports it in Search Console’s Page Indexing report, grouping URLs by status and reason. It is the single most useful view for diagnosing whether pages that should rank are even eligible to.

How it works

The report buckets URLs into indexed and not-indexed, with reasons for exclusion: “Crawled — currently not indexed” (a quality or duplication signal), “Discovered — currently not indexed” (a crawl-budget or capacity signal), “Duplicate, submitted URL not selected as canonical,” “Page with redirect,” “Excluded by noindex,” and 404s. Read as a trend, sudden movement between buckets is how you catch a template change, a canonical mistake, or a crawl problem before it costs traffic. Being indexed is the floor for ranking; a page excluded here cannot rank at all.

Where it applies

• Enterprise sites — where thousands of URLs slip into “discovered, not indexed” and signal crawl or quality limits.
• Migrations — the fastest confirmation that the new site is being crawled and indexed as intended.
• Ecommerce — where thin or duplicate faceted URLs cluster in the exclusion buckets.

What matters from each seat

• In-house — watch the reason breakdown over time; the shape of exclusions tells you what to fix.
• Engineering — “Crawled, not indexed” at scale usually points to quality or duplication, not a bug to patch.
• Agency and consulting — the coverage report is the evidence base for an indexation audit and a clear client narrative.

From the field

Rebuilding a baby-registry brand’s technical base for search and AI ingestion, a lot of the win lived in the coverage report: cutting crawler page size by more than 70% and modernizing prerender and schema so pages stuck in “discovered — currently not indexed” finally got crawled and indexed. Coverage isn’t a vanity report; it’s where you see whether your fixes actually landed.