Canonical: how it works and when to use it
LightSEO · Technical SEO
Canonical: how it works and when to use it
Canonical is a way to tell a search engine: "this page has several URLs, and this one is the main one". The tool is simple, yet mistakes with it cost you pages in the index.
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canonicals to a non-existent page
Where it's needed
Typical use cases
Filters and sorting. A page with parameters points its canonical to the clean category.
A product in several categories. If the URL depends on the path, the canonical points to the main one.
Pagination. Here the canonical points to the paginated page itself – pointing it to the first page makes products from deeper pages drop out.
Tracking parameters. URLs with ad parameters point to the clean version.
Mistakes
Why canonical fails
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Chains
Page A points to B, and B points to C. The search engine may simply ignore the whole setup.
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Pointing to a blocked page
The canonical leads to a URL blocked in robots or marked noindex – the signal is contradictory.
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Everything to the homepage
A mass canonical to the homepage drops half the site out of the index.
Key points
What to remember
Canonical is a hint for the search engine. The search engine may choose a different page as canonical if the signals contradict each other.
Canonical should be self-referencing. A regular page points to itself – this is normal and correct practice.
Are pages dropping out of the index as duplicates?
We will check your canonicals, redirects and indexing rules – and put things in order.
