Canonical URL
The address Google treats as the main version of a page when the same content can be reached at more than one address.
The same page can often be reached at several addresses: over HTTP and HTTPS, as separate mobile and desktop versions, as US and UK copies of the same content, or with the sorting and filtering options of a category page added on. Google calls these duplicates and says some duplicate content is normal and not a violation of its spam policies (Google Search Central).
When Google finds pages that look the same, it groups them and picks one as the canonical. It crawls that page most often, uses it as the main source to judge content and quality, and usually points search results to it.
Can you choose it?
You can say which address you prefer, and Google weighs signals such as HTTPS, redirects, whether the address is in your sitemap, and rel="canonical" link annotations. In Google’s words, your preference is “a hint, not a rule”: it may choose a different page.
Why duplicates cause trouble
Google notes that the same content at many addresses can confuse visitors and make it harder to track how your pages perform in search results. Before you pay for a tool that sets canonical links, check what your store or website platform already does.
Related terms
Tools for it
Sources
Updated Oct 7, 2026.