Canonical URLs: What Are They And Why Are They Important In SEO

What Is A Canonical URL?

A canonical tag is nothing but an HTML element that helps site owners to prevent copying content issues in search engine optimization (SEO) by identifying the “canonical” version of the web page. Let us take an example of a canonical tag. This HTML code tells crawlers that the URL “” is the authentic version of the page that has this tag.

<link rel=” canonical href=””  />

What Is The Use Of Canonical URL And When To Use A Canonical URL?

Canonical tags are very useful in search engine optimization, with the help of canonical tags you can protect your website from duplicate content, for both externally and internally. Internal duplicate content is caused on your website, but external duplicate content does not happen on your website, it happens when duplicate pages exist on different domains.

Now we know that what is the use of canonical tags, but another big question arises in our mind when to use a canonical tag?

We do not have any formula for using canonical tags on our website, it only depends on the situation. Many search engines use canonical tags to identify what pages to show and hide on search engine result pages. Canonical tags are either referencing on another page or referencing itself.

1. Canonical URL Referencing Itself:

If there is a single version of this page, then make sure that canonical tags referencing itself, it plays a significant role because it gives information to a search engine that “show only this page in search engine results” so that only that page shows on search engine results that you want.

2. Canonical URL Referencing Another Page:

If the same page has multiple versions, then it is important that the canonical tag is referencing that page which you prefer to be shown by search engines.

There are many ways in which canonical tag can prevent duplicate content issues:

  • When querying parameters are used in URLs.
  • When multiple versions of the page were created.
  • When pages are similar to each other.

A.) Query Parameters In URLs:

URL sometimes contains query parameters depending on the URL structure of a website. Query parameters in the URL are used to get some particular information. Let us take an example.

  • In this example the variable lang=us represents the language for the requested page is English (US).
  • Another variable in this URL represents that you want to open page number 343.
  • If we talk that why we use “&” in this code, it means that we want to open page number 343 whose language is English (US).

But query parameters can easily create the problem of duplicate content. For example  opens the exact same page as, However, the URL of both the pages are different. But you can easily fix this problem with the help of the canonical URLs.

B.) When Multiple Versions Of The Page Were Created:

Sometimes, you have to create multiple versions of a page. For example, personalized landing pages for campaigns.

But when you make multiple versions of the same page, then make sure to use a canonical tag on that page which you want to show on the search engine result page.

C.) When Pages Are Similar To Each Other:

We have to create many pages that contain similar content for marketing purposes and for any other purposes. Let us take an example of an e-commerce website that sells the latest smartphones if you want Samsung Galaxy NOTE 20, which is available in Violet, Pink, and White color. But when you select a different color, URL, changes, but nearly the content is the same on every page. Then you can solve this problem with the help of canonical tags.

For example,

Samsung Galaxy NOTE 20:

Samsung Galaxy NOTE 20 In Violet Color:

Samsung Galaxy NOTE 20 In Pink Color:

As we see, that the content on these pages are very similar, that’s why it makes sense to have a canonical URL from and pointing to

In these cases, canonical URLs help you to prevent duplicate content issues.

What Does A Canonical URL Look Like?

As we read above, canonical tags are very important for good SEO. Now, let’s see how a canonical URL looks like. Your visitors are not able to see canonical tags when they are visiting on your website or on your blog. Canonical tags can be defined only in page source or in HTTP Header.

1. Page Source:

Let us take an example, that is how a canonical tag for our home page looks like.


<link rel=”canonical” href=””  />


This is the best way to define a canonical tag for your home page.

2. HTTP Header:

If you want to use a canonical tag in a non-HTML document, then we define the canonical tag in the HTTP header. Let us take an example to understand how to define a canonical URL in the HTTP header:

HTTP/1.1 200 OK

Server:  apache

Date: Mon, 31 Dec 2019 10:43:18 GMT

Content-Type: application/pdf

Content-Length: 11453

Last Modified: Fri, 4 Jan 09:38:33 GMT

Link: <>; rel=”canonical”

With the help of this example, you can define a canonical tag in the HTTP header.

Different ways to canonicalize multiple URLs.

Canonical URL often referred to as rel=”canonical” is an HTML element that tells the search engine that a stated URL represents the master copy of a page. Canonical tags are important because they prevent problems that are caused by identical content by duplicate or similar content appearing on multiple URLs. They play a vital role in making sure that the SEO strategy is strong. There is no doubt in saying that, SEO is really very important for every website. Canonical URLs matter, as they help to specify the URL that should be shown in the search results. They help you to deal with duplicate content issues that could affect the performance of your site immensely.

There are various ways to canonicalize multiple URLs for the best on-page SEO practice, they are as follows:

1. By using the location hash:

A hash can be added in the URL, in any search engines like Google, and it will be considered as a single URL. generally referred to as fragment identifiers or fragment URL is a URL that ends with “#” which is used to specify a particular section on a page. This would not rank the content differently but, it will be canonicalized with the same URL.

2. By using a 301 direct:

You can use 301 redirects in order to specify canonical URLs. it is one of the best-proven ways to resolve duplicate content issues. Basically, 301 redirects tell the search engine that you want to create a permanent redirect from one URL to another. These redirects also help to link various URLs together, so that search engines could rank all the locations based on the domain authority from coming in links.

3. By using passive parameters in the search engines dashboard:

You can use passive parameters in the search engines console and tell them which parameter you would like them to consider passive. Substantially, you can tell Google that whenever you see a particular URL parameter, whether to pop it up on the screen or not.

Why are canonical tags important for SEO?

A canonical tag defines the main version for duplicate and similar pages. You can use canonical tags to specify the version that is main if you have similar content available under different URLs. Canonical tags are vital for SEO strategy. They help in conveying the search engines that there is a relevant page that helps to resolve issues with duplicate content. If you choose the right canonical URL for every set of similar URLs, it will help in improving the SEO of your site. Also, because duplicate content is very bad for any website and it confuses the search engines and it can drop your website to rank high in the search engine results page. Read about different SEO strategies, that help in improving SEO ranking.

Hence, here is a list to find out why are canonical tags so important for SEO?

1. They ensure that relevant URLs rank for keywords:

Canonical tags help to ensure that relevant URLs rank for queries. If you use rel=canonical, you can avoid situations like competing of the two URLs of your website with each other for the same keywords on the search engine results page. If you do so, just make sure that you mention the proper canonical URL that you want Google or any other search engine to index and rank in the canonical tag. This is an important part of your SEO strategy.

2. Canonical tags help in saving the crawl budget:

Canonical tags should be used to save you from crawl budget. If you mention a canonical tag, it helps the search engines to analyze which URL to index and rank out of different versions of the page. This way the web spider, also known as a crawler will not have to waste time crawling pages that have been canonicalized. And, that the web spider could reach other important URLs on your website and save your crawl budget.

3. Canonical tags help in the allocation of link juice:

Canonical tags ensure that the link has been passed to the correct version of the page. Search engines properly distribute link juice to all those different pages who have similar content. If you use a canonical tag, you let search engines decide the page you want to give importance to and rank in the search engine results page. It then disregards all the duplicate pages and passes on the link juice to all the important pages making it sure that there is a proper allocation of link juice on your website. It is one of the most important factors for gaining top ranking in the search engine.

Case Study:

In this section, we will talk about India’s largest e-commerce website (Flipkart) which uses canonical tags to solve their duplicate content issues. As we all know that with e-commerce sites, the problem is having the same products in a different color, size, and memory. Now we will take the example of a product with different colors.

iPhone X comes in three different colors white, pink, and black.

When the customer searches for the iPhone X on google, then the URL of the first result then it takes me to the iPhone X (White) page.

When customers search the same query on the Flipkart site which listed all the three colors. These are the URLs of the pages.




Every time when the customer search for iPhone X then it takes the customer to iPhone (white) page, which kills the experience of the customers because customers do not get any choice in color of iPhone which is not right, but when the check the code they find that White iPhone’s page has been defined as the parent page of all other iPhone pages, then they use canonical tags to solve this problem and make https://www/ as a parent URL so that the customer can choose their favorite color which improves the experience of the customer and also increases the sales of Flipkart.


A canonical tag is nothing but an HTML element that helps site owners to prevent copy content issues in search engine optimization (SEO). Canonical tags are very important for SEO because it protects your website from duplicate content issues. Canonical tags prevent duplicate content issues in the following ways.

  • Query Parameters In URLs.
  • When Pages Are Similar To Each Other.
  • When Multiple Versions Of The Page Were Created.

Canonical tags are defined only in the page source or in the HTTP header. There are different ways to canonicalize multiple URLs.

  • By using the location hash.
  • By using a 301 direct.
  • By using passive parameters in the search engines dashboard.

Canonical tags are very important for SEO because,

  • They ensure that relevant URLs rank for keywords.
  • Canonical tags help in saving crawl budget.
  • Canonical tags help in the allocation of link juice.

I hope that after reading this summary, you may get a brief introduction about the canonical tags and why they are important for SEO. If you want to get detailed knowledge about canonical tags then go and read the whole article thoroughly.


In this article, we talked what are canonical tags, what is the use of canonical tags and when to use canonical tags, we also looked that how a canonical tag looks like, we also get the knowledge of different ways to canonicalize multiple URLs, we also talked about why canonical tags are important for SEO, in the last, we discussed a case study of India’s biggest e-commerce website Flipkart, which gives us the right path for using of canonical tags in your site. I hope that you liked these points related to canonical tags. Then what are you waiting for? If you also run a website and you want your website to rank on the first page of the search engine, then use canonical tags carefully to increase your SEO score.

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