This translation has not been editorially reviewed yet. The German version is authoritative. Deutsche Fassung →
Checking the canonical URL: which address applies to a page
The canonical address tells the search engine which URL is authoritative for a piece of content. It's needed as soon as the same content is reachable under several addresses — with and without www, with parameters, in print views. The check verifies whether it's set and points to a valid address.
- With no canonical address, the search engine decides for itself which version to index — and ranking signals spread across several addresses instead of consolidating on one.
- Two mistakes are common, and both have real consequences: a canonical address that points to the homepage instead of the page itself (the page then disappears from the index), and one that points to a redirected or unreachable address.
FAQ
Does every page need a canonical tag?
It never does harm, and it helps wherever parameters, sort orders, or session identifiers can create additional addresses. A self-referencing tag is the simplest safe state.
What happens with an incorrect canonical tag?
In the worst case, the page disappears from the index, because it points to a different address as authoritative itself. That's one of the few mistakes that can make a well-built page invisible.