Google’s John Mueller has advised that using rel=canonical does not necessarily guarantee that Google will recognize a page as the canonical version.
Mueller shared this insight in a Twitter reply to a user who was puzzled as to why Google was indexing the “wrong” page rather than the one designated by rel=canonical.
The user was specifically concerned about Google indexing page 3 of a paginated series instead of the first page.
In response, Mueller explained that Google considers multiple factors when determining the canonical version of a page.
“Rel=canonical isn’t a guarantee,” Mueller said. Therefore, it’s not uncommon for Google to index a page not intended to be the canonical version.
He also mentioned that using rel prev/next could conflict with rel=canonical.
Mueller recently advised a site owner on Reddit against mixing rel=canonical with a noindex tag.
“Signals such as redirects, rel=canonical, internal & external linking, sitemaps, hreflang, etc., help convey your preferences. The more aligned these signals are, the more likely Google will follow them and choose a canonical from that set.”
Looking back at the user’s Twitter query, and considering Mueller’s Reddit advice, a possible conclusion can be drawn.
Google might recognize page 3 of a paginated series as the canonical version due to other signals that hold more weight than rel=canonical.
For instance, if more external links point to page 3 than to page 1, Google might decide page 3 is the best version to index in search results.
This is just one possible explanation, but it’s clear that Google uses a variety of signals to determine the canonical version of a page.
While rel=canonical helps guide Google, it does not guarantee canonical recognition.
