What is A Canonical URL? A Manual for SEO

We answer all your burning issues concerning canonical URLs, from duplicate content to how Google may select your canonical sites.

The term “canonical tag” is frequently used in conversations about SEO, maybe more so when collaborating with partners from different cross-functional fields like engineering, analytics, etc.

It could appear frightening at first, especially if you are somewhat new to the SEO industry.

The good news is that this article will go into the specifics of what a canonical tag is, why it matters, how it appears in the wild, where it belongs, and other pertinent information.

What is A Conical?

First and foremost, before we even establish a canonical tag, let the following be the most important lesson you learn from this guide: Canonical tags do not function as robots.txt file directives.

This means that while Google sees canonical tags as a strong hint, it ultimately weighs a variety of signals before deciding whether to honour them.

Now that we have cleared that up let’s move on to the actual golden rule.

To inform search engines which URL is the master version of a page, the canonical tag was introduced in 2009 and can be found in the source code of HTML documents. You can use this to instruct Google on which page variation to the index for users.

The HTML tag is a canonical tag, although the term “canonical” is slightly different.

A user-declared and a Google-declared canonical are two straightforward approaches to describing canonical variations.

User-declared canonical: This is the canonical that was specified in the canonical tag and does exactly what it says.

This is the URL that Google has designated as the canonical version.

The URL Inspection Tool in Google Search Console can be used to view both of the aforementioned canonical types.

In a perfect world, they would match, but what if they didn’t? Next, we shall expand on that.

How Does Google Select A Canonical URL?

When crawling and indexing a website, Google examines the page’s main content.

Google will probably find comparable pages during this crawl; it will then decide which of these pages best captures the message the carrier seeks to get across to people and designate it as canonical.

As we stated previously, a canonical tag is not a directive, so be consistent. Google also takes other signals into account.

Only a few of the different criteria Google takes into account using a canonical tag are internal links and external links.

Attention: There is a reasonable probability that Google may disregard your canonical meta tag and prefer a URL with a query parameter as the canonical if you internally link your pages with query parameters like /?some parameter=xyz.

Make sure your defined canonical matches the URLs in your RSS feed because Google scans RSS quite aggressively.

There is a risk that Google will choose a canonical with the query string e /?source=feed even though it is a tracking parameter, and Google is aware of that if you add URLs to your RSS feed with parameters like /?source=feed to track visits to your site from RSS subscribers.

Use RSS services like Feedpress or link-shortening services for your RSS feed URLs if you want to be able to track clicks on them.

Google will make decisions based on the user experience.

Google may serve the mobile version of your site to a user on a mobile device, even if your site also has a desktop version.

How the Use of Canonical Tags Can Benefit SEO

Canonical tags are crucial for websites with a few pages and those with millions of pages.

They are required for a variety of reasons.

You Choose The Canonical Tag

The canonical tag gives you a chance to tell Google which version of a page on your website is the best one to offer visitors.

Repetition Of Content

Duplicate content is a topic that appears straightforward at first glance but is more intricate than its name suggests. It also frequently carries a bad connotation.

You might be saying to yourself, “I don’t have any duplicate pages,” but let’s take a quick look at what Google Search Central Documentation defines as “duplicate” before you say that.

Any pages with the same primary content in the same language are duplicates. Assume you use several carriers to handle both dynamic URLs that aid with parameters or session IDs and mobile pages (an m., amp, etc.).

In such instances, your site contains the same material, an HTTP and HTTPS version, and your blog creates paths in several directories. Given its prevalence and lack of cause for alarm, this is of canonical relevance.

Google’s primary source is Canonicals

To assess the quality and substance of a page, Google uses the canonical.

More often than non-canonical pages, the canonical is crawled.

It Might Help With the Budget for the Crawl

If your site is relatively large, you’ve probably heard the term “crawl budget” mentioned quite a bit.

When appropriately used, Canonicals can reduce the strain on your crawl budget because Google will crawl canonical versions of pages considerably more frequently than non-canonical ones.

This is not a substitute for robot directives, redirects, or no-index tags.

Combine Link Signals

Canonicals direct search engines to combine their diverse data for several related pages into a single URL, enhancing its value.

Syndication of Content

Make sure your version of the content appears in the search results if you operate a website that syndicates its content for publication or is used by partners.

The Best Way To Use A Canonical Tag

Let’s speak more about how to add a canonical tag on your website now that we have covered the what and why of canonical tags.

When a page’s version is the most effective for consolidating things like statistical tracking, HTTPS versions, mobile experiences, etc., it can (and should) contain self-referencing canonicals.

You will likely need to collaborate with your development/engineering colleagues unless you can alter the HTML directly.

A canonical tag is a code added to the head> section of any page.

It may appear as follows:

Canonical Tag FAQS

Is it Possible to Canonical Across Domains?

A: Without a doubt, you can. Using a canonical tag, for instance, will concentrate all the power on the version you chose as the canonical if you publish the same article across multiple domains. This is a wise course of action for syndicated content best practices when working with websites you do not own.

Are Canonical Tags Link Equity Passing?

A: The general agreement is that they do, although canonicals shouldn’t be confused with 301 redirects.

No-Index tags or canonical tags—which should I use?

A: A no-index tag is a directive, first and foremost, instead of a canonical tag, which is meant to remove a page from the index. A canonical tag is a fantastic approach when you combine all the links and relative signals into one URL.

It depends on which is our go-to response in the SEO industry related to this query. John Mueller goes into greater detail on the questions to ask yourself when deciding between using a canonical or noindex in an SEJ, where he outlines when to use both.

Is a 301 Redirect or Canonical Tag Better?

A 301 is a directive, just like a no-index tag. Again, the answer is “it depends,” but there are a few factors to consider before picking one over the other. A 301 redirect might be a smart option if you have two highly identical pages and don’t need to have them active for business purposes.

A product page that is indefinitely out of stock or an outdated page that isn’t worth upgrading would be two ideal examples. In this post that discusses 301 vs canonical tags in detail, you may read more use case scenarios.

What Happens If Google Isn’t Respectful to the Selected Canonical?

A: As was previously mentioned, there are instances when Google might need to honour the canonical name you’ve specified. You can view this information using the URL Inspection tool in Google Search Console. Google may need to respect the user-selected canonical for several reasons.

The tag may need to be implemented correctly, site signals may conflict with the chosen canonical, and there are several additional issues. You’ll need to conduct some analysis to identify the underlying problem.


We hope that this explanation of canonical tag usage has clarified the what, where, and why for you. Review your canonical tags to see where you can make changes to help search engines find your preferred information.

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