Canonical SEO Tags – How to Use Them for SEO Optimisation Success

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According to Google’s head of search spam Matt Cutts, 25 to 30 per cent of content on the Internet is duplicative. It means that several content pieces look almost exactly the same as other existing content. When this happens, how do search engines like Google resolve the issue to avoid bombarding their users with duplicate articles?

Glad you asked. For instance, Google will automatically pick two or more versions to display in the SERPs, choosing the page that it thinks is the most relevant. They will mark what’s canon and what’s not, even without your permission or knowledge.

That’s why canonical tags were introduced in 2009 by Bing, Google and Yahoo. Without canonicalisation, your content can be viewed as duplicate and allow search engines to choose the canon of your site.

This, in turn, may put your rankings, search visibility and digital marketing on the line. 

If you’re reading this guide, then you’ve come to the right place. Let’s take a look at what canonical means in SEO along with friendly practices recommended by SEO agencies.  

What is a Canonical Tag?

A canonical tag is an HTML code that helps search engines identify which pages have original content and which are duplicates. 

The tag goes in the page’s <head> section and looks like this:

<link rel=”canonical” href=””>

Having this tag establishes the appropriate authority and ranking position of your website’s content without the fear of penalty for having a duplicate circulating the web. 

Why is it Essential to Have Canonical Tags?

Duplicate content refers to content that appears at more than one URL on the web. They are defined as pieces of content that seem exactly similar, ranging from exact copies of content to content that includes phrases of identical texts. 

why it is essentials to have canonical tag

Source: Moz

This might sound dreadful, we know. But there’s no need to fret because having similar content can sometimes be inevitable, like quoting another article you found on the search results page. 

There are two types of duplicate content you should know:

  • Also referred to as cross-domain duplicates, external duplicate content takes place when two or more domains contain the same page indexed by a search engine.
  • If one domain creates duplicate content using multiple internal URLs on the same site, this is when internal duplicate content happens.

Let’s give you an example. Imagine you run an e-commerce website that mainly sells official band shirts. Your URL looks like this:

To improve conversion rates, you launch a sales campaign and the same products are posted on this link:

Since you’re hosting similar products, descriptions and images at two different URLs, Google will view it as duplicate content. 

But did you know that not all duplicates can jeopardise your SEO optimisation campaign? 

As a content creator, you want to attract as many audiences as possible to support and consume your content. This moves you to promote your content on other pages to advertise it more and direct more readers back to your website. 

This is where canonicalisation plays its part. Canonical tags head up Google and other search engines that the ‘duplicate’ pages are only second pages and that the first page is still the original content. 

Failure to include a canonical tag may result in Google choosing the canonical URL, and it might not be the accurate one suitable for the original version of the content. 

Here are some tips on how you can fully maximise the advantages of canonical tags:

Promote Original and High SEO Value Content

When you are in the SEO industry, keeping up with the intense competition in the B2B marketing scene means that you should establish a competitive content strategy

If you only rely on creating duplicative content, you tell search engines that your website does not provide relevant information to visitors. This can affect your overall rankings, SEO performance and credibility. 

That’s why learning how to publish original and quality content remains an unparalleled tactic in helping web crawlers properly index your page. Check out these tips on how to create and promote SEO-friendly content:

  • Use killer headlines and subheadings. 
  • Optimise your images.
  • Add high-quality links to your content to increase the chances of ranking higher on the SERPs.
  • Write SEO-friendly URLs.

Optimise Your Crawl Budget

If your content has duplicate pages and lacks canonicalisation tags, search engine crawlers may go through all of these duplicates. 

You know what this means. If bots spend too much time crawling on duplicate pages, they will miss some of the most valuable, unique content you have. 

Avoid wasting your crawl budget; implement the process of canonicalisation.  

Boost Ranking Position

Another thing why canonicalisation is essential, it affects your ranking ability. 

A large-scale content duplication harms your ranking capability on the search engine results page (SERP). If there are too many versions of your content, search engine spiders may have difficulty finding the most relevant to the queries searchers key in online. 

Keep in mind to avoid having multiple versions of the same page and highlight the most valuable content of your website for users and search engines. 

When to Use Canonical Tags

When it comes to using canonical tags, many SEO experts don’t share similar views on the subject. Strategies aren’t really set in stone, so the process of using canonical tags may vary.

However, there are common instances—aside from duplicate content—where implementing canonicalisation positively contributes to your website and SEO practices. Take a look at these scenarios:

Similar Content

One of the most popular instances where canonical SEO tags become necessary is when you run an e-commerce site. This is especially true when you sell products that seem so similar on the surface but have hard-to-identify differences.

In this case, using canonical tags helps search engines prioritise the main product page, boosting your ranking on the SERPs. It will also likely reduce the confusion for search engines in deciding which page to rank!

URL Parameters

Also known as query strings, URL parameters are elements added to your URLs to help you track information and organise content on your website. 

But the problem is, every parameter created for the main URL sends a signal to search engines that they might be duplicated versions of the same page. To solve this issue, you have to label the main page as the canonical one so it doesn’t harm your overall SEO performance.


Lots of SEO agencies didn’t think that self-referencing canonicals were important until Google announced in 2017 that this practice helps them in determining the original content URL.

It is highly recommended that you should add a canonical tag on each page, even if they don’t have an obvious duplicate. For example, there are several ways to reach and view your URL. So let’s say you have ‘’. A visitor may also reach your site by typing ‘’, ‘’ and many more.

And when you include a canonical tag to these URLs, Google will know that it’s just one page and what they should index for the search results page. 

301 Redirects vs Using rel=canonical

If you’re not certain if you need canonicalisation or just simply implement a redirect, here’s what you should consider:

Use a redirect if you have extremely similar pages and you don’t need both of them because of certain reasons. This includes:

  • Products you no longer want to sell.
  • Pages removed from your website.
  • A web page that has been moved to a different URL.

Keep in mind that 301 redirects are not recommended for temporary purposes. Content delivery networks (CDNs) may permanently cache it, making it almost impossible to undo. 

However, using canonical URLs is the best choice if you want to keep both versions of a certain page to be available for users and using redirects isn’t achievable. They can also serve as great band-aids for poorly constructed URL structures. Here are some examples:

  • You see unwanted parameters from a paid search campaign. Through canonical tags, you can get prevent these unnecessary marketing URL strings from getting displayed in the SERPs.
  • Sorting or categorisation of pages. For example, a URL contains similar products but they are sorted according to prices (high to low).
  • The ‘print version’ of a page.

SEO Benefits of Canonicalisation

Canonicalisation is essential to SEO for many things, but the most obvious reasons are:

  1. Enhance Crawling Activities

Your website will benefit more if you improve your crawling activities. Having a canonical tag helps you signal search engines to efficiently crawl pages that you want bots to find and index. 

Duplicate pages waste crawl budget and time as bots and spiders might get into insignificant content to crawl and index rather than the critical content you want them to focus on. 

  1. Consolidate Link Equity

Having duplicate content can have backlinks that may take over the link equity of your original content. 

If you share pieces of your content on various external sources but fail to have a conical tag, it can affect the main version of that content’s ranking chances. 

Canonical tags can improve ranking in Google search results as they can transfer a PageRank into a single URL. 

  1. Manage Syndicated Content

Canonical tags signals search engines the original version of your website’s content and separate it from the content you have republished.  

We are sure that you have done this and continue to do so now – using other websites to publish your content either for promotional purposes or others. 

If you are practising this content strategy, you must understand that it will be hard for Google and other search engines if you don’t have a canonical tag. 

The lack of it might confuse search engines on what content should they be displaying as a search result and which website to promote or highlight. 

  1. Solve the Duplicate Content Issue

Of all, probably this point makes a lot more sense why you need to consider having canonical tags. 

There are scenarios in which people use category-based queries or tags to look for information, and they serve with the same results. 

Content duplication confuses search engines’ crawlers. As people use Google to search for content, it matters that you direct them to the right and preferred page you want bots to crawl and index. 

Multiple links can cause you to lose the value of links on your page. Canonical tags help search engines with the link of your content that you want it to show to the users when they make queries. 

To save you from this issue, ensure you know how and when to have a canonical tag. 

Canonicalisation and Pagination

What is Pagination? 

Pagination is an SEO technique that divides content across a series of pages. This process is common for websites to ensure the organisation of the content and helps users navigate the site better.

The following types of websites that widely use pagination are:

  • Blogs
  • Forums
  • News Publishers
  • E-Commerce

Google recently announced an update through its Twitter account that it no longer uses pagination with rel=“next” and rel=“prev” as an indexing signal. 

This recent update on Google’s end means that they no longer use this link to:

  • Consolidate indexing properties and 
  • Identify the most significant paginated page to rank.

Traditionally, SEO experts tend to use canonicalisation to optimise paginated pages. 

This process reduces indexing bloat, which can improve the ranking of low-quality content on your website. Unfortunately, this tactic is unacceptable as it can negatively impact your other pages’ rankings. 

Google’s documentation states that “when Googlebot indexes a site, it tries to determine the primary content of each page. If Googlebot finds multiple pages on the same site that seem to be the same, it chooses the page that it thinks is the most complete and useful and marks it as canonical.”

This statement means that Google undergoes many signals and processes a page before deciding on a canonical page. Those pages that Google failed to select are no longer considered and indexed. 

Once Google excludes paginated pages from indexing, this will drop signals to those pages and the content associated with – internal links, articles, product URLs, etc. 

It will remove the link authority and relevancy of those pages, and this will leave you with an orphaned page that may affect your website’s Google search rankings. 

Canonicalisation and Hreflang

You may think that canonical tag and hreflang are the same. They both tell search engines which version they must index and show to users but these tags don’t function in the same way. 

What is Hreflang?

Hreflang attribute (rel=”alternate” hreflang=”x”) helps webmasters with international websites to deliver the correct localised version of their content to their respective searchers. 

Google introduced this in 2011. Since then, it has become a website’s most essential attribute.   

Hreflang tag sends signals to search engines about the language your searchers use to access specific content of your website.

Do you know that hreflang can also be a tool if you want to target regions that speak the same language?

Yes. You can use hreflang attributes to reach English users in countries that don’t use English as their main language. 

So what’s the difference between canonical tag and hreflang tag?

The canonical tag tells search engines the page’s ORIGINAL version that they should index. 

While the hreflang tag signals search engines about the language and region version of that page. 

How to Find Canonicalisation Issues on Your Website 

Since canonicalisation is one of the complex elements of your SEO campaign and optimisation, it is totally fine to encounter issues with it. 

There are available SEO tools that can assist you in finding these canonicalisation issues or duplicate content – the likes of Ahrefs, Moz, Screaming Frog or SEMrush. 

These tools allow you to simply plug in your URL. They release a report containing detailed information about which pages lack canonical tags and suggest solutions you may implement to fix these identified issues. 

Here are some ways to fix your canonical issues:

  • Perform 301 redirects for duplicate pages
  • Add canonical tags for all of your website’s pages.
  • Check and ensure that external sites where you share your content include a rel=canonical tag that points back to the original version of the content. 
  • If your site is both available on mobile and desktop, pick only the site that you intend to serve as the canonical version.  

The Process of Canonicalisation 

Use a “rel=canonical” tag 

Adding a canonical tag in your HTML is one of the most frequently used ways to implement it. 

In your duplicate page’s <head> section, you may add this code: 

<link rel=”canonical” href=”” />

Caveat!: This method works on HTML pages alone. There is a different approach for HTTP headers. 

Use a “rel=canonical” HTTP header 

As mentioned, here’s how you can implement canonicalisation for non-HTML documents:

 Link: <>; rel=”canonical”

You need to access your site’s server, and this method will require some technical knowledge. Many times this approach causes more harm than improvement on some websites. So, if you are not sure, you might as well stick with HTML. 

Use Absolute URL 

Absolute URLs save you from facing errors and bugs. 

Though Google is open for both absolute and relative URLs, absolute versions are less to give you a headache. 

So refrain from using only the URL path, and include the FULL URL in a canonical tag. 

Use Lowercase URL 

In our previous article, we shared that one of the best practices for writing your URL is in lowercase form. 

URLs are case-sensitive. Adapting lowercase letters to craft your URLs prevents linking errors within or outside your website. 

You may argue that search engines don’t mind websites having mixed lower cases and uppercase URLs. To save you from future problems, ensure you have your URLs in lowercase form. 

Right now, almost all CMS automatically convert uppercase letters to lowercase in a page URL, as WordPress does. So, there’s no need for you to panic if you still have mixed or uppercase URL structures. 

Use Correct Domain Version 

If you decide to switch to SSL, don’t forget not to include any non-HTTPS URLs in the canonical tags. You will only face issues in the long run. 

Use Self-Reference Canonical Tags 

This is not a golden rule, but we recommend it. 

John Mueller of Google said that “it’s not critical to have a self-referencing canonical tag on a page, but it does make it easier for us [Google] to pick exactly the URL that you want to have chosen as canonical.”

Google uses many factors to pick canonical URLs. So, it is essential to implement self-referential canonicals to utilise parameters to track campaigns. 

Use 1 Canonical Tag per Page 

Be clear and straightforward. 

If you want search engines to notice and spend time on your website, ensure that you send a clear message to them – use only one canonical tag per page. 

Sending mixed signals to search engines can influence them to incorrectly interpret your canonicals. Worst, they will pick the wrong version as canonical and have it on search results. 

Common Mistakes While Setting Canonical SEO 

There are best practices that you can implement, and there are those you have been doing the wrong way for quite some time. Maybe, these are the mistakes you need to correct from now on.

Canonicalised URL blocked on robots.txt

Google will not crawl your content if you block the canonical URLs via robots.txt file. To avoid canonical issues, be mindful of double-checking or triple-checking your robots.txt file and reviewing the directives you set on it. 

Canonicalised URL has 404 HTML Status Code

Avoid at all costs the 404 status code. 

For canonical URLs, this status code will have the same effect as the “noindex” tag. Meaning, that Google will not see the canonical tag and will not forward whatever link value it has to the canonical version. 

Having Multiple Canonical Tags

You should never have multiple URLs for your site’s article or product description.

You know how search engines work. Its crawlers allocate resources for each crawling activity, and having multiple canonical tags can waste the bots’ time checking those various versions. 

Keeping your tags unique and ready for the index can positively influence your crawl budget optimisation and your page’s ranking position.  

Set up Canonical SEO with YOAST

You may be wondering right now how you can set up, add, or change canonical tags to your pages. We want to remind you that adding or changing canonical tags depends on what type of website you are maintaining. If you are a subscriber of a WordPress site, you can use Yoast as an SEO plugin to add canonicals to your website. Check this one out!

  1. Log in to your WordPress website.
  2. Go to the post, page, or taxonomy for which you want to change the canonical URL.
  3. Once you are in the editing screen, go to the ‘Advanced’ section in the Yoast SEO sidebar or a meta box.
  4. Enter the full canonical URL, including http/s and www or non-www, in the ‘Canonical URL’ field.
  5. Update the post, page, or taxonomy.

If you are using SEO plugins for your WordPress E-Commerce sites or website, you don’t have to worry about the process of adding or changing them. These plugins come in a very navigable and straightforward interface. 

Set Up Canonical SEO with Rank Math

To set up canonical URLs on your site using Rank Math, here are the steps you need to take:

Step # 1: Edit The Page

View the post or page that contains duplicative content. To get started, click the Edit button. 

edit canonical seo using rankmath

Source: Rank Math

Step # 2: Click the Advanced Tab of Rank Math

Proceed to the Advanced tab of Rank Math in your editor after you’ve opened the post. Make sure that you turn the advanced mode on from the WordPress Dashboard if you can’t find the Advanced Tab.

Rankmath canonical setting

Source: Rank Math

Step # 3: Replace the Canonical URL

You can modify the Canonical URL field to point to the main source of your content under the Advanced tab. That way, it will inform web crawlers of the main page if you have posts with the same content.

Step # 4: Save The Post

If you’re done making changes to your canonical URL, click the Publish button if it’s a newly established page. If it’s an old post, just update it like you normally would and you’re done!

Set Up Canonical SEO on Shopify

One of the most common SEO issues that Shopify store owners experience is duplicate content. This includes product pages that are shown on several distinct URLs, like outlet pages, bestseller pages or on-sale pages, to name a few.

Another example of duplicate content in Shopify is your Shopify-managed domain and your primary domain. If you’re facing the same issue, this is how you set canonical SEO on the platform:

  1. Go to the admin panel. Under Online Store, click Themes.
  2. To pick the theme you want to edit, click Edit Code under Actions.
  3. Select theme.liquid under Layout.
  4. Insert the following code on the line above the closing </head> tag and click the save button:


{{ page_title }}{% if current_tags %} &ndash; tagged “{{ current_tags | join: ‘, ‘ }}”{% endif %}{% if current_page != 1 %} &ndash; Page {{ current_page }}{% endif %}{% unless page_title contains %} &ndash; {{ }}{% endunless %}


{% if page_description %}

<meta name=”description” content=”{{ page_description | escape }}” />

{% endif %}

<link rel=”canonical” href=”{{ canonical_url }}” />

Set Up Canonical SEO on WIX

If you’re using WIX, bear in mind that the platform automatically generates a default canonical URL for all of your posts. And to change a post’s canonical tag, here are the steps you should follow:

  1. From your site’s dashboard, view the Blog section.
  2. Click the post you want to edit.
  3. Select SEO on the left side.
  4. Select Advanced.
  5. Select Additional Tags.
  6. Under Default Meta Tags, click the Tag Settings icon beside Canonical.
  7. Under Tag Value, input the URL in the box.
  8. Select the Checkmark.
  9. Save changes. 

Final Thoughts

Learning the ins and outs of canonical SEO tags can feel overwhelming, especially when you’re just beginning to understand the technical side of SEO. However, when you fully wrap your head around it, you’d appreciate how canonicalisation is meant to complement traffic-generating SEO strategies. 

When you implement canonical tags, you take matters into your hands. You tell search engines like Google and Yahoo which URL is original and should be ranked, and which ones should be disregarded. 

Without canonical tags, Google will play guessing games that can negatively impact your rankings in the long run. 

Moreover, following the best canonicalisation practices can help web crawlers respect the canonical tags you apply. This includes implementing the robots.txt file, identifying duplicate content on your pages and using self-referential canonical tags, among many other things.

As your SEO professionals and strategists, we take every small detail into account. At Roots Digital, our SEO services offer you the best practices for sustainable growth and industry-approved standards. 

We would be delighted to tag you along in our SEO journey. Book an appointment with us now!

Frequently Asked Questions

What is Canonical SEO?

Canonical SEO (rel=canonical attributes) main purpose is to manage duplication and preserve the website content’s link equity. 

Why do canonical tags are important for SEO?

Canonical tags are vital for SEO because it:

1. Enhance Crawling Activities
2. Consolidate Link Equity
3. Manage Syndicated Content

You may not find this practice helpful at the moment, but canonicalisation plays an integral role in search engines and search engine optimisation.

How do I add Canonical?

If you are using a plugin like Yoast, you may add canonical tags by:

1. Logging in to your WordPress website.
2. Next, access the post, page, or taxonomy for which you want to change the canonical URL.
3. Click on the ‘Advanced’ section in the Yoast SEO sidebar or a meta box.
4. Enter the full canonical URL, including http/s and www or non-www, in the ‘Canonical URL’ field.
5. Update the post, page, or taxonomy.

Then you are good to go!

Keep Learning

Understanding canonicalisation may open so many opportunities for your SEO campaign and can help you better in positioning your website. 

Many SEO practices may seem too complex to apply and may get too overwhelming to study.  Optimising your website for SEO is an exhilarating activity and a chore to deal with, especially if you don’t have a solid SEO background. 

Worry no more, as Roots Digital are here to help you in your optimisation journey. 

Consider these topics to add to your SEO knowledge or if you simply want some refreshers:

Looking for a trusted SEO agency in Singapore? Schedule a consultation with us today.

About Roots Digital

Roots Digital is an award-winning digital marketing agency and SEO agency headquartered in Singapore, specialising in eCommerce Marketing and lead generation.

Some of our core digital marketing services include SEO servicesSEM services, Google Ads management servicesGoogle Analytics services and more.

Feel free to reach out if you’re interested in working with us. Connect with us via our service enquiry form. You may schedule a call for more information and to know more about our digital marketing services.

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Picture of Ian Ong
Ian Ong
Marketing Director @ Roots Digital, a digital marketing agency in Singapore. Aka the guy responsible for growing the digital marketing agency.
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