Search engine optimisation (SEO) is an aspect of digital marketing that has numerous terms and expressions specific to it. Some of these are self-explanatory, and others are not. One such term, which may not immediately make clear what it is, is ‘canonical tags’; however,  it is an SEO term that every website owner should not only be aware of but also know is essential to their SEO and quest to achieve higher search engine rankings.

In this article, we are going to explain what canonical tags are, how they work, their importance within SEO, and, crucially, how you create them within your website for optimal results, including a step-by-step process you can easily follow.

What Are Canonical Tags?

A canonical tag is a small piece of code that can be added to the ‘Head’ section of a website’s HTML code. Its primary function is to inform search engines that crawl the website which version of a page is the preferred or ‘canonical’ version.

The reason for having it is that when a search engine indexes a website, it can find more than one version of the same page, with each one having a unique URL. This can lead to duplicate content issues and confusion for search engines.

For example, if you have two pages on your website with the same content, but different URLs, search engines may not know which one to index. This can lead to your website being flagged as having duplicate content and a subsequent lowering of your search engine rankings.

How Do Canonical Tags Work?

When a search engine crawls a website, and it finds multiple versions of the same page with different URLs, it will seek a canonical tag so that it can determine which version of the page it should index.

In the ‘Head’ section of the correct page for indexing, the attribute “rel=canonical” is added to create the canonical tag. As such, a canonical tag must be used only once across several pages to avoid further confusing the search engines.

Why Canonical Tags Are Important?

There are several reasons why you might have multiple versions of the same page. It could be you are doing some A/B testing, or you might be testing a plugin or some coding and wish to try it on the duplicate pages rather than the live one. There may be other reasons, but whichever reason applies, you must alert search engines which of the pages is the preferred one that they should index and rank.

If you do not do this using canonical tags, it is possible that the search engines perceive your website to be using duplicate and, worse, spammy content, and that can mean your rankings suffer considerably.

How To Implement Canonical Tags On Your Website

The process of creating canonical tags for your website is relatively simple; however, if you are unsure or simply averse to doing anything technical to your website, you should reach out to either the web design agency that created your website or to an SEO agency who will be able to help you.

Step #1 – Identify Duplicate Content Issues: The first step is to identify if you have duplicate content on your website. The fact is, many website owners are not even aware that they have any duplicate website pages, so this step will confirm if this is the case or not. This will also identify which pages have duplicates. You can use tools such as Sideliner, Screaming Frog, or Google Search Console for this task.

Step #2 – Determine the Canonical Version: This should be straightforward as often the page you want to be indexed is obvious. By ‘obvious’ we mean that the second or subsequent pages might be incomplete, have missing images, or have fulfilled their purpose as part of a test. However, if the pages are identical, then we suggest selecting the version of the page which was published first.

Step #3 – Add the Canonical Tag: Once you know which page is the one you want to be indexed, you should now create the canonical tag. The specifics of this will be influenced by how your website was created. It can be done by adding the attribute “rel-canonical” to the raw HTML code; however, if your website is built using WordPress, the canonical tag can be added using an SEO plugin such as Yoast SEO.

Step #4 – Test Your Canonical Pages Are Indexed: Once you have added the canonical tag, you must check it is working properly. Otherwise, the problem with duplicate pages could continue. Use Google Search Console to confirm that the correct ‘canonical’ version of the page is indexed.