Canonical URLs: A Beginner’s Guide to Canonical Tags
21 Feb

Canonical URLs: A Beginner’s Guide to Canonical Tags

By priyanaidu

Knowing Canonical and how you can correctly use it is essential for SEO. Executing canonical wrongly can lead to various problems that negatively affect your website’s ranking.

It was first propounded in 2009; canonical tags have to assist web admins in solving the issues of widely-similar or duplicate content available on various URLs. Still, if you want to use the canonical tag, you need to know what it is, how it works, and how to execute it.

Definition of Canonical URLs or Canonical Tags:

Canonical URL could be an HTML element that guides the search engine to ignore all other page versions and seek the one marked within the canonical tag for ranking purposes. This comes in handy when you have duplicate pages with similar content, and you don’t want search engines to classify them as the same content.

They can be located in the HTML code of a page under the head tag. It can further point to its URL or a few other pages’ URLs for consolidating signals to the search engines.

A canonical URL or link could be the version of the content you want your viewers and Google to see in place of other duplicate pages.

How does a canonical URL look?

Canonical URL or canonical tag could be an easy-to-use syntax placed under your web page’s <head> section. This is what it looks like:

<link rel=”canonical” href= />

SEO advantages of canonicalization and why does it is necessary?

The search engines could not admire duplicate content. The reason is that it builds finding the correct version of a page hard for both index and ranking purposes. In addition, the same pages cause cannibalization problems wherein ‘link equity’ gets split between duplicate pages with similar content. This way, none of the pages brings a ranking benefit.

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In addition to this, having more duplicate content on your website can negatively affect your crawl budget. This means that search engines will be wasting a lot of time crawling similar pages’ same versions rather than finding necessary content.

You should ignore duplicate content as you don’t want search engines to waste time crawling through the pages you do not want to rank. Still, according to Google, even if you have duplicate content, it won’t be a problem. If your website has fewer than a thousand URLs, it will be expertly crawled in ample cases. If you are facing issues because of the crawl budget, canonical URLs can assist in solving these. Through these, search engines will learn which page’s version they are required to index and rank.

So what happens when you have not mentioned a canonical page?

If you do not add a canonical tag, search engines will use their choice and identity a page that their algorithm thinks is the great version. If they choose an arrangement that you don’t want to rank for, this can be a problem. By the way, search engines may not at times respect the canonical URL set by you. They don’t use the URL as choices but as hints. Using great practices for canonical URLs should reduce the risk of search engines using an unpleasant version as canonical. Primarily, make sure that the pages you cannibalize are related.

Reasons why duplicate content persists?

In a few cases, building duplicate or ‘appreciably similar’ pages is deliberate as they serve various purposes.

Take an instance where you have customers in various countries. In this case, you will require two product pages that have different prices but are otherwise nearly alike. Depending on the user’s location, you can use canonical URLs for these pages to guide search engines on which page to serve. Also, there may be a few technical reasons for having duplicate content, and you may not even know about it. If you have a changing website or use content management systems, you may have duplicate pages or content.

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A few websites recklessly add tags permitting multiple paths to similar content parameters such as sorts, searches, or currencies. So, this may end up building numerous duplicate titles on your website without you being known to it. Thankfully, with canonical tags, search engines can find a variety of variations of a page and ignore problems associated with duplicate content.

Multiple URLs with similar content- what’s the mess?

When there could be duplicate content on your website, it can influence your rankings and make you lose traffic. These wastes come from the following two problems:

  1. Search engines do not display duplicate versions of the content to give a great experience. So, they pick an understanding that they think is a good result. If this takes place with you, the visibility of your duplicates will be weak.
  2. It can also weaken link equity as different websites pick between duplicates. So, rather than inbound links pointing to a single content, they will link to distinct pages and spread the link equity.

Duplicate content can also build problems for the search engines:

  • They don’t know the version that should be included or excluded from the index. Or don’t know whether to direct the link metrics to a single page or split it between various pages.
  • It don’t know that which page should be ranked for query results.

Canonical URLs great practices:

Executing canonicals is simple. Here are a few great practices you can use:

  • Using absolute URLs: you should not prefer to use relative paths for the rel=”canonical” link element. So, rather of using this structure: <link rel=”canonical” href=”/tutorial-page/” /> you should try this structure: <link rel=”canonical” href= />
  • Use lowercase URLs: it is achievable that the search engines may consider lowercase and uppercase URLs on your website and use similar ones for your canonical URLs.
  • Using a correct version of the domain(HTTPS vs. HTTP): if you shift over to SSL, you should not proclaim non-SSL URLs in the canonical URLs. Doing this may direct you to undesirable results and more confusion. If your website is a safeguarded domain, rather of URLs following version: <link rel=”canonical” href= /> you should try the following version: <link rel=”canonical” href= />. If you are not trying HTTP, the other one of these will be right.
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Use self-referential canonical URLs: self-referential canonical URLs could be a canonical tag that points to a similar page. Even though trying a self-referential canonical tag is not compulsory, it is advisable. This is because it clarifies what pages are to be indexed to the search engines. There can be various URL variations, whether because of parameters in the end or because of uppercase and lowercase. All of this is washes up using real canonical URLs. So, if the

  • URL is, the self-referential canonical will be: <link rel=”canonical” href= />. A few famous CMS that will recklessly add a self-referential canonical URL. In the case of custom CMs, you may require a developer to hardcore this.
  • Using a single canonical tag per page: if your web page has various canonical tags, the search engines will skip all of them.


As stated earlier, canonicalization is an essential concept for SEO. Without proper execution, your website will not perform as effectively. That being said, once you know what canonical URLs are, what canonical tags are, and how you can solve canonicalization problems, you will be able to try and use them properly and take care of duplicate content on your website.