Definition
The canonical tag (rel='canonical') is an HTML element placed in the head of a page to tell search engines which is the main URL when multiple URLs display the same or very similar content. It resolves duplicate content issues without redirection, by consolidating SEO authority on the canonical URL. For example, if a page is accessible via different URL parameters or with/without www variants, the canonical tag indicates which version should be indexed.
Key Points
- Resolves duplicate content without redirection
- Consolidates SEO authority on the preferred URL
- Place in the HTML head: <link rel='canonical' href='URL'>
Practical Examples
Sort parameters
A product page accessible via /product, /product?sort=price, and /product?sort=reviews uses a canonical pointing to /product to avoid duplicate content.
Pagination
Pages 2, 3, 4 of a listing can point their canonical to themselves while using rel=prev/next to indicate the pagination relationship.
Frequently Asked Questions
It's a strong suggestion. Google respects it in most cases but may ignore it if it seems incorrect (e.g., canonical pointing to a completely different page).
Yes, cross-domain canonical is supported. It's useful when the same content is published on multiple sites, to indicate which version is the original.
Go Further with LemmiLink
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Last updated: 2026-02-07