A Practical Guide To Canonical Tags

canonical tag

Want to learn about canonical tag and how to use it to prevent from duplicate content errors? You have come to the right place. Well, only to let you know, Canonical tags have been around since 2009 created by the collaboration of Google, Yahoo and Microsoft to resolve the duplicate content errors easily and quickly. So, do they function properly? Yes, absolutely but only when you have an idea to use it precisely. These tags are used in SEO to support the search engines add the correct URL and prevent the use of copied content. In today’s blog we will deep dove into the detailed concept of canonical tag to help you understand its meaning and significance.

What is Canonical Tag?

It is HTML specification appears in the header section of a website’s source code. It is the canonical URL, the master page that helps websites for concerns related to similar content. It defines the primary version of a duplicate, similar pages or near duplicate. In simple words, if as a user you have a same content under distinct URLs, you can take help from the canonical tags to determine and index the key version on the website.

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How Does a Canonical Tag Look Like?

The canonical tags of an HTML snipped use a simple and compatible syntax that are in the header section of webpage.

A basic canonical tag example is given as:

<link rel=’’cannonical’’


The meaning of each of these codes are:

1.      Link rel=’’cannonical’’: Here the link in the tag is the master version of this page.

2.      mba=’’https”//illustration.com/sample/page/’’/>: The canonical version can be discovered at this uniform resource locator.

Why Canonical Tags Are Significant To Search Engine Optimization?

Google search engine doesn’t prefer the similar content pieces as it makes difficult for the search engine to select:

·         Which page version needs to be indexed?

·         Which Page versions should rank to get the related queries.

·         Whether the search engine should fuse the link equity on a single page or divide it among multiple page versions.

A bulk of similar content pieces often leaves a negative impact on your crawl budget. This means the search engine like Google, Bing have to invest too much time crawling over different versions of the single web page in place of finding other essential content pieces on your website’s blog.

But if you use the canonical tags, your all issues can be resolved within no time. The HTML snippet tells the search engine of which webpage version they should rank and indicate. If you cannot determine a canonical URL, the search engine will take over the complete task in its hands. Although, depending on the search engines should not be your option as they may pick up a webpage version which you never want to be canonical. The search engine respects the canonical URL, but sometimes that’s not the case.

How To Apply Canonical Tags on Webpage?

It is quite easy to apply canonical tags on a webpage. But before we jump onto those ways, let quickly recall the five golden rules of applying canonicals on a page. These are-

#Rule1: Add Absolute URLs

To rightfully apply the canonical tags to the page, do not take the rel= canonical link element with the relevant paths. Instead, you can use the below mentioned structure.

<link rel=’’cannonical’’


In comparison with the following structure:

<link rel=’’canonical’’ mba=’’/sample page/’’/>

#Rule2: Use Lowercase URLs

Since many search engines may treat the lowercase and uppercase URLs, ensure to add the lowercase URLs on the serve and then use it well for the canonical tags

#Rule3: Use the Right Domain Version

If you prefer the SSL, ensure that you do not define any HTTP URLs in the canonical tags. Exercising so, can cause unexpected results and misunderstanding. If you are using a safe domain, ensure that you are using the below URL version for your webpage:

<link rel=’’canonical’’


In comparison with:

<link rel=’’canonical’’


#Rule4: Use Self Referential

Using the self-referential, canonical tags are referred to others. But if you are unsure how it works, it’s a webpage’s canonical that points to itself. Maximum CMS include self-referencing URLs automatically but it requires a developer hard code.

Rule4: Use one Canonical Tag for Each Page

If your page has over one canonical tag, then it is possible that your search engine would avoid them all. Thus, it is very essential for you to add single Canonical tag for each page.

Implementing Canonicals

There are five different methods to define canonical URLs, called canonicalizations signals. They are –

·         HTML tag

·         HTTP header

·         Sitemap

·         301 redirect

·         Internal links

1.      Set Canonicals Using HTML tags

Use a rel=canonical tag by adding the below code to the header section of the similar content page. It is the easiest method of defining a canonical URL.

<link rel=’’canonical’’


2.      Setting Canonicals using HTTP reader

There is no method to locate the canonical tags in the header section of the page for PDFs document. In such situation you will have to set the canonicals in the HTTP reader format.

3.      Set Canonicals using sitemap

Google states that only canonical URLs should be listed in the sitemaps to see the listed pages on a large site. Therefore, you should use the sitemap to set canonicals in order to tell Google which page your website consider the most important among others.

4.      Set Canonicals with 301 redirects

When you aim to divert the website traffic away from a similar URL towards the canonical version, use the 301 redirects that works best for the case.

5.      Internal links

Using the internal link through the canonicalizations signal is the best method to be more consistent, which eventually allows you to define your preferred canonical URL to the search engines.


The canonical tags are that complex, but is bit difficult to understand initially. Only keep in mind that canonical tags are signals for search engine. It tells the search engine that there is a standard resource to resolve the issues related to duplicate content. It helps it to prefer and crawl the unique content and give it a better rank on the search engine result pages, resulting in a better visibility of the content.

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