Google — Consolidate duplicate URLs (canonicalization doc)
Google’s first-party reference on duplicate/overlapping pages and how to pick a canonical URL. The primary-source grounding for the traditional-SEO half of keyword-cannibalization.
Key facts
- Why duplicates hurt. Three documented costs: signals “such as links” get split across the duplicates instead of consolidating to one URL; duplicates waste crawl budget that should go to “new (or updated) pages on your site, rather than crawling duplicate versions”; and they make “consolidated metrics for a specific piece of content” harder to get.
- What canonicalization does. It consolidates “the signals they have for the individual URLs (such as links to them) into a single, preferred URL.”
- How Google picks one absent a signal. Google “will identify which version of the URL is objectively the best version to show to users in Search,” and auto-prefers HTTPS over HTTP.
- Three ways to specify a canonical, ranked by strength: redirects (“a strong signal”),
rel="canonical"annotations (“a strong signal”, via HTML<link>or HTTP header), and sitemap inclusion (“a weak signal” — Google still verifies duplication independently).
Tier
T1 — primary first-party Google Search Central documentation.
Related
keyword-cannibalization · authority-density · search-indexation · google-search-essentials · search-marketing