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What Is The Rel Canonical Tag?

The rel=canonical tag is a bit of code that tells Google which version of a website page is the one you want Google’s crawlers to pay the most attention to (i.e., the canonical page). It is a good option for handling duplicate content situations that naturally arise on a website — and from an SEO point of view, for making sure Google ranks your canonical version of a web page most highly and most often.

“Duplicate content” sounds like poison when you’re talking about SEO, but the fact is Google expects duplicate content and even offers instructions on its Search Console for consolidating duplicate URLs. Typical situations causing duplicate content include: 

  • HTTP and HTTPS versions of a page
  • HTTP://www.example.com versus HTTP://example.com
  • Mobile version of a page and a desktop version of a page
  • When e-commerce pages have search options that let you sort products by size, color, price, etc.
  • When internal search engines create new URLs for search results (when a visitor searches on your site)
  • When blog posts are reproduced on other websites

To Googlebots (Google crawlers), these pages may have the same or almost the same content, but are nevertheless distinct, separate pages — even though human readers may not even realize they are looking at different pages from session to session.

If you don’t use rel canonical tags to tell Google which version of the page is the one you want to display in search results, Google will make the determination. You might end up seeing the wrong version of the page coming up in SERPs (search engine results pages) or several versions of the page coming up in SERPs, with none of them achieving the desired ranking.

Rel Canonical Tags and Link Signals 

In SEO, you get the biggest bang for your buck by putting as much of Google’s attention as possible on only one version of a page, the canonical page. This matters not only for ranking, but also for linking signals. When you have a canonical page, links pointing to all versions of that page are credited to the canonical page — very significant! This is why it is always a good idea to create a canonical version of your home page, because most people link to a site’s home page and people may use any number of URLs to execute the link.

Rel Canonical Versus No Index 

It’s important to use rel canonical tagging only for pages that are identical or nearly identical. If you succumb to temptation to try for an SEO shortcut by setting up tags for pages with varied content, Googlebots are likely to ignore the tag. There is also data that suggests that Google views rel canonical tags as a hint rather than a command, and therefore it is possible for versions of a page you don’t want indexed and ranked to be indexed and ranked anyway.

If you have pages with similar content and you want only one page indexed, you’re better off using a “noindex, follow” tag, which is a directive that prevents Google from indexing your non-preferred pages.

The rel canonical tag has been around since Google introduced it in 2009. Over the years, best practices for its use has evolved, and will continue to do so. Large websites, whether for lead generation or e-commerce, should review their canonical pagination strategy at least annually, and check more frequently than that to determine whether Google is indexing only the canonical versions of the page. If the canonical structure is out of date or flawed, it could be that your SEO efforts are being seriously diluted without you’re even being aware of it.

To talk about duplicate content issues or a new SEO campaign, contact us now or call 855-883-0011.