Canonical URL is a URL which we specify for search engine preference. That is, search engine bots find it difficult when a website has two pages with the exact same content, but with different URL.

So, by adding a canonical tag we tell to search engine:

Ok search bot, I have two pages with similar content and I know you might be confused. So use this canonicalized URL as the preferred URL while indexing my page

Let us take an example, below mentioned URLs all direct to the same home page:

Right now, there is no canonical tag present in “”.

Google itself took “” as the preferred URL to index the page (Refer below screenshot) without canonical url

Now, if we want to change this and use “” as the preferred URL then the best way is to add a canonical tag on both “” and “

The canonical tag that needs to be added is:

“<link rel=”canonical” href=”“/>”

Now, let’s answer your next question:

Does this always work?

In almost most of the cases canonicalizing your URL might solve your duplicate page issue. But, sometimes even when you canonicalize your URL Google and other search engines might not take that into consideration.

So, after canonicalizing the URL it is highly recommended to redirect the unwanted duplicate page URL to the preferred original page URL.


Importance of canonicalization in terms of SEO

  • Canonicalizing your URLs helps in improving your page authority.
  • Helps in consolidating the link signals of the duplicate pages into a single page. That is let’s say both “” and “” has separate back links from different websites. Now when you add a canonical URL and put up a redirection, all the backlinks now point to a single webpage.
  • Consolidates traffic metrics of different duplicate page URL into a single page URL. This helps in tracking the daily user traffic of the website.
  • Prevents unwanted URL getting indexed in Google and other search engines.

Types of duplicate pages:

Types of duplicate product page URLs

Source: Google Search Console Help


Important things to note while adding a canonical tag:

  • Use 301 redirects for redirection of duplicate page URLs.
  • Give preference to HTTPS over HTTP for canonicalization.
  • Do not use robots.txt file to add a canonical tag.
  • Use the same canonical tag for all the duplicate pages.
  • If there is a sitemap, make sure that the URLs present in sitemap are the same as the preferred canonical URL.


What is a canonical URL and why it is important for SEO?