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What is Canonical Tag? Its Importance in SEO

NIDMM ~ Modified: November 21st, 2023 ~ SEO ~ 6 Minutes Reading

Do you know? What is canonical tag ?

What is canonical tag? The Canonical tag in SEO is an HTML code element that is basically used to indicate the version of webpage you want and should appear on search engine result page when user makes a query.

Canonical tags have been in existence since 2009, making them a well-established solution for any canonical issue.

Canonical tags were developed collaboratively by Google, Microsoft, and Yahoo. Their primary purpose was to offer website owners a simple and efficient method to address problems related to duplicate content.

At times a canonical error occurs where multiple version of the same content exist but with different URLs. Such canonical issue may effect you webpage indexing and ranking.

The Canonical tag is primarily employed to address duplicate content issues that can arise on the internet due to various reasons such as different URLs for the same content, HTTP and HTTPS versions, session IDs, printer-friendly pages, etc.

But here’s the catch: canonical tags work flawlessly only if you understand how to implement them effectively!

In this blog, we will learn about what is a canonical tag. Also, we will know why it is important for SEO and how to implement canonical.

Also read- 9 Important Technical Issues that Matters in SEO

What is the structure of a canonical tag?

A canonical tag is represented by “rel=canonical” in HTML code, serves as a valuable tool for identifying the primary version of duplicate, near-duplicate, or similar web pages.

The canonical tag typically appears in the <head> section of an HTML page and follows this format:

<link rel=“canonical” href=“”>

The “href” attribute should contain the URL of the webpage you want to appear on search results. When a search engine encounters this tag, it understands that the specified URL is the one to be considered for ranking and indexing purposes, while treating the other versions as duplicate.

Simply apply canonical tag when you have identical or similar content accessible through various URLs, implementing canonical tags allows you to indicate which version should be considered the main one and indexed accordingly.

By implementing the canonical tag properly you can prevent potential SEO issues caused by content duplication. It also helps in ensuring that the correct version of a page appears in search engine results, improving the overall user experience.

Why are canonical tags important for SEO?

Now you must have understood what exactly is canonical tag in SEO. But do you know why are these tags important in terms of SEO?

Let’s understand the importance of these tags one by one.

Google has a strong aversion to duplicate content, as it presents several challenges for them:

1. Indexing Dilemma

Duplicate content confuses Google in determining which version of a page should be indexed. Due to this, they will only choose to index one version, potentially ignoring the others.

2. Ranking Ambiguity

When faced with duplicate content, Google struggles to decide which version should be prioritized for relevant queries. This can hinder your page’s chances of ranking well in search results.

3. Link Equity Distribution

Duplicate content complicates the distribution of “link equity.” Google has to decide whether to consolidate the value of incoming links on one page or distribute it among multiple versions. This can impact the overall ranking potential of your content.

4. Crawl Budget Allocation

Excessive duplicate content can also affect your website’s “crawl budget.” Google may spend valuable crawling time on multiple versions of the same page, leaving fewer resources to discover and index other crucial content on your website.

How to Implement Canonical Tags?

To implement canonicals effectively, follow these steps:

Identify Duplicate Content

Begin by identifying instances of duplicate content on your website. This can occur for various reasons, such as multiple versions of a webpage (e.g., HTTP and HTTPS, www and non-www), session IDs, parameter variations, or printer-friendly versions.

Determine the preferred version

Once you have identified the duplicate content, determine the preferred version of each page. This preferred version should be the one              you want search engines to index and display in search results. Factors to consider when selecting the preferred version include                          relevance, user experience, and any existing backlinks or ranking authority associated with that specific URL.

 Implement Canonical Tags

Once you have identified the preferred version of each page, you need to implement canonical tags. A canonical tag is an HTML element           placed within the <head> section of a webpage. It specifies the canonical URL that search engines should treat as the primary version.

Implement 301 Redirects (if applicable)

In addition to canonical tags, you may also need to implement 301 redirects if you have multiple URLs with identical or similar content.           By redirecting duplicate URLs to the preferred version, you consolidate ranking signals and prevent the dilution of SEO efforts.                           Implement 301 redirects using server-side redirects or through your website’s content management system (CMS).

 Update Internal Links

To reinforce the use of canonical URLs, update internal links throughout your website to point to the preferred version. This includes                navigation menus, internal content links, and sitemaps. By ensuring that internal links consistently point to the canonical URLs, you                enhance search engine understanding and reinforce the preferred version’s authority.

Monitor and Maintain

After implementing canonical tags and 301 redirects, regularly monitor your website’s performance and crawl errors using tools like                 Google Search Console. Check for any new instances of duplicate content or errors and make the necessary adjustments. It’s crucial to               maintain the correct implementation of canonicals as your website evolves and new content is added.

Implementing canonicals correctly can help consolidate your website’s ranking signals and prevent the negative impact of duplicate content on SEO. By guiding search engines to the preferred version of a page, you improve its visibility and increase the likelihood of it appearing in relevant search results.


In conclusion, we understood what exactly is a canonical tag in SEO, and how it looks like. Also, make sure that the tag has its own importance in terms of SEO and how important it is to implement it properly.

Now, we know when the search engines crawl websites, they might come across duplicate content, which can lead to problems like reduced search rankings or indexing of the wrong version of a page.

By adding the canonical tag to a page’s HTML code, webmasters can signal to search engines which version of the page they consider as the primary or canonical version that should be indexed and ranked.