Just add a rel=”canonical” link to the head of a page to tell search engines which URL you want treated as the authoritative version of similar or duplicate content.
You use canonical tags to consolidate indexing signals (links, content relevance) and reduce duplicate-content issues that can split your pages’ visibility. This helps ensure your preferred URL ranks and that analytics and link equity are not fragmented across variations.
Use this syntax in the HTML head of the page you want to de-duplicate: . Always use the full absolute URL (including protocol) and point to the final, working URL that returns a 200 status.
Apply canonical tags when you have multiple URLs serving the same or near-identical content: parameterized URLs (tracking, sorting), HTTP/HTTPS or www/non-www duplicates, print or AMP versions, faceted navigation, and session IDs. If pages are intentionally different, do not canonicalize them to a single URL.
Follow these implementation steps: 1) Audit your site to find duplicate or similar URLs with crawling tools or Search Console; 2) Choose a single preferred URL for each content group; 3) Add a self-referential canonical on the preferred page and canonical tags on duplicates that point to the preferred URL; 4) Use server-side templates or CMS settings to apply tags consistently; 5) Test and monitor results in Search Console and with crawlers.
Avoid common mistakes: do not canonicalize to pages that return 404/301/500 errors, avoid chains (A -> B -> C) and loops, and do not point canonicals at pages blocked by robots.txt. Prefer self-referential canonicals on every page to make your preference explicit, and avoid using relative URLs in the canonical link.
Test your implementation by viewing the page source, using crawler tools, and checking the Index Coverage and URL Inspection tools in Google Search Console. Allow time for search engines to process changes and monitor which URL they choose to index; they may override your tag when they detect substantial differences or signals.
If you need to indicate a canonical on a different domain (cross-domain canonical), point the href to that domain’s canonical URL and ensure the target allows crawling. For language-targeted pages, combine canonical tags with hreflang correctly: canonicalize only truly duplicate content, and use hreflang to signal language/region variants.