What Is a Canonical Tag and How Can It Help Your SEO?

Do you know why your website ranks where it does on a search engine results page? Would you like to improve your site’s ranking?


It would be nice if Google provided a full report as to why a website ranks where it does. Unfortunately, even the most experienced SEO professionals don’t have the full answer sheet. Over time, however, Google and the other search engines provide the public with information on how they can improve their search ranking by implementing technical changes to their website. One of the biggest evolutions to come out of these releases, and still one of the most misunderstood, is the development of the canonical tag.

What does a canonical tag do?

A canonical tag specifies the source URL (or original content page) of a given page to a search engine such as Google. Canonical tags are used to declare a single page as its own source or for duplicate pages to reference their source / originating page. Search Engines use the canonical tag to combat duplicate content issues and assign search engine ranking  value for that content to the page designated as the “source” URL.

Why do canonical tags matter?

Duplicate content is a big no-no to search engines. Having pages of identical or very similar content on your website is seen as a negative, and may be used by Google to devalue your website when determining rankings. If you use https on your site, utilize a content management system like WordPress or Drupal, or run an eCommerce website, the combination of different URLs people can use to access your website opens you up to a major SEO vulnerability if not properly addressed. By properly employing canonical tags to pages on your site, you can avoid this pitfall and take full advantage of both a robust site and streamlined Search Engine Optimization practices.

How do I apply a canonical tag?

On the pages that you want Google to recognize as canonical, add a link tag to the head of the HTML code. For example, to designate www.LTnow.com with the canonical tag, the code would look like:

<link rel=”canonical” href=”https://www.ltnow.com” />

Rinse and repeat for every page on your site you want to make canonical. Again, the use of a Content Management System such as WordPress can streamline this effort.

What pages should I put the canonical tag on?

As many as appropriate. Visits from social media, internal site search, referral links, and other inbound references all have the potential to generate a unique URL that could have a negative impact on your website’s rankings. Additionally, many content management systems allow for multiple URL paths to access the same content. All of these paths can be crawled, and Google potentially could identify them as separate pages of duplicate content.

If you aren’t sure if issues with duplicate content are affecting your SEO, we can perform a full SEO Audit of your website to identify issues that impact how your site is crawled and where it ranks. Once you know what the issues are, you can get started on fixing them. Contact us and we can get started right away!

  • Can you use multiple canonical tags for one page if that page uses content from multiple other pages.

    Ryan Robey
    Independent Rebuild Specialist

  • Uriel Palmer

    I’m still not understanding what a canonical is? Let’s say I have multiple pages that have been optimized for SEO but I point all the pages to the main domain? Does that give the domain ranking power?

    • eppand

      Uriel, it is a complete misuse of the canonical tag to point interior pages to the he page. That would kill your content’s ability to rank in the SERPs. Canonical help to provide direction on URLs that generate duplicate content issues or if you are syndicating content and need to source the original content.

      • Uriel Palmer

        I see. Does google process click through rate apart of their algorithm? It seems unfair for new and upcoming sites to not get first page results but a page from 2008 manages to stay, even if the information is outdated and no longer relevant. I’m aware of changing the search time period to get more updated info, but most people don’t change that and end up clicking on some of these old articles, and if that’s the case, how do you knock a site down from it’s perch?

        • eppand

          Uriel, the question seems simple, but SEO isn’t as cut and dry and “current” content. I do believe the Google calculates / evaluates SERP on CTR and if a user returns back to Google quickly. But there are so many more factors that influence your performance and ability to rank. Domain age and authority are certainly factors + backlinks, social, on-page signals, and so much more come into play. There is no one magic elixar to overcome a site or ranking. Each scenario is unique.

          • Uriel Palmer

            Ok. Thanks for your information. I appreciated you taking the time out to answer my questions.

  • Fredy Wenger


    Interesting posting, but I can’t really understand, if it is relevant for me.
    We have a public portal that – unfortunately – is based on a proprietary AJAX-based software.
    => For this portal, I had to implement an ugly “SEO-Router” to feed the spiders (give back a plain HTML-Page for each entry)
    I’m on the way to create a brand new portal now based on ASP.NET 5.
    In our portal, there are more then 30’000 customers stored (each with unique data).
    I need direct links for every customer.
    The easiest to reach that, would be to use ?-parameters to a (same) controller and then dynamically load the data to the customer (from SQL-Server), create the page and give back the page.
    So the sitemap would look like:

    Whereby each page is unique to the others (as the content is different for each customer).
    Is this a case for a canonical tag or not?

    And… if yes, the tag should be (for the example):

    Thanks for an answer

  • Canonical
    tag is use to tell search engines the original source of the article. This is
    also to solve duplicate content issues on site.

  • Many developers tell to add code in function.php and in header. Is it beneficial to use in header tag and function.php file these codes?

    • eppand

      Humna, the canonical tag should only be included once per page. I would recommend the functions file but the header file would also work. It should be rendered in the area if your HTML. This effort should help with duplicate content issues, but it’s not a magic arrow. It depends on the full scope of thw duplicate issues on this being the full remedy. Thanks!

  • I could not understand about these tags. But still I am facing issue of duplicate content in Webmaster tools. I also have posted many questions, how to rid duplicated content. But could not get answer of this question. If really this tag will work then I will use.

  • “If you use https on your site, utilize a content management system like WordPress or Drupal, or run an eCommerce website, the combination of different URLs people can use to access your website opens you up to a major SEO vulnerability if not properly addressed. ” – Why using HTTPS could make it worse? Just wondering.

    • eppand

      HTTPS opens another combination of URLs. If https and https both render with duplicate content, you may be self inflicting the problem.

      • “if https and https both render with duplicate content” – do you mean “if http and https both render with duplicate content”

        What if I use the HTTPS for all my cases and use 301 to redirect every request of HTTP to HTTPS?

        • eppand

          Yes to HTTP v. HTTPS.

          Yes to 301 one to another.

  • Shams

    Hi eppand,
    I have All-In-One SEO plugin installed on one of my wordpress site. I see the plugin is adding canonical ref in every URL/page to it’s own URL (ex. example.com/hello.php, canonical=”example.com/hello.php”). Just to be stay safe, is it good practice?

    • eppand

      Yes, it is good practice for a page to list its own URL as the canonical.