What is Canonicalisation and what does it mean for your SEO?

Canonicalisation sounds like a daunting concept, especially to those less well-versed in technical SEO. The complicated word often causes online marketers and web designers across the globe to shudder at the thought of having to tackle a technical problem that involves comprehending this sixteen-letter behemoth.

But it’s really not that scary. We thought it’d be handy to break this intimidating idea into a bite-size blog post to demonstrate how simple it really is.

What is Canonicalisation?

Simply put, if you have a canonicalisation issue then you have a problem with your URLs. It means that either your on-page content exists in more than one place or that there are dead pages that exist on your website that you didn’t know about. The duplicate URL problem may be present on a small scale (i.e. a page existing in more than one place) or on a larger scale (i.e. an entire website existing in more than one place) but either way, it’s a problem that needs addressing. Here are a few examples of what I mean:

Single page duplication: It could be that two versions of an entire website can exist simultaneously. E.g. your site exists at both http://example.com and http://www.example.com. This will mean that every single one of your pages has been duplicated.
 

URLs that you didn’t know about: It might be that your website exists at http://www.example.com but does not load at http://example.com i.e. if a user types example.com directly into a browser’s search bar.

Why is canonicalisation such a big deal?

Unfortunately, canonical problems make it a lot harder to rank well in search engines. Here’s why:

Indexation problems in search engines: If you have more than one occurrence of the same page, Google’s web crawlers will have a tough time deciding which URL is the correct one to display in search results. This will result in the bots either guessing which is correct or worse not indexing any of them!
 

Unclaimed link juice: It is possible that several other websites are linking to you, but that they are all linking to different URLs despite linking to the same content. If for example, your blog posts exist in multiple places as in the example above, your content could be earning great inbound links, but a canonicalisation problem will mean that these links are being spread across more than one URL, thus giving link juice to several weaker pages rather than a single strong one.
 

Duplicate content: The Google Panda update first rocked the SEO world back in 2011 by clamping down on identical content being published in more than one place. Since then it has become critical to solve duplication issues, and canonical URLs can result in lower rankings due to this duplicating content.

Poor user experience: Imagine you are running an offline marketing campaign that encourages users to type your website directly into their browser. If, as in example three above, your website does not redirect correctly, when a potential customer types in your URL without the ‘www.’ they will see a 404 error page instead of being redirected to your homepage.

What about cannibalisation?

Another phrase you’re likely to encounter with canonicalisation is the idea of cannibalisation. The two words sound quite similar, but they have a distinct difference. Cannibalisation refers more to the contents of your pages, rather than their technical composition with things like URLs.

Essentially, if you have content or pages that are too similar, they can compete against each other in the search engine results pages (SERPs).

So what do I need to do to solve it?

In most instances where canonicalisation is present, you will need to get your web developers to redirect the URLs into just one version. This will usually be solved by either setting up a 301 redirect or adding new instructions into the .htaccess file that controls how your website’s URLs are generated. 301 redirects should be put in place carefully with a fully formed redirection strategy to ensure search engines continue to find all your relevant web pages.

Canonical tags

You can also use canonical tags to indicate to search engines which web page should be used for ranking purposes. A canonical tag should always be in place even if it’s pointing to itself.

When it comes to duplicate or very similar content a canonical tag which looks like this: rel=canonical <link> should be put in place to indicate which version should be considered by a search engine when ranking. Add a <link> tag in the code for all duplicate pages, pointing to the canonical page. This ensures you have created a canonical URL, which Google’s developer documents describe as “the URL of the page that Google thinks is most representative from a set of duplicate pages on your site.”

You can use Google Search Console to help you find out if any canonical issues could be affecting your SEO efforts. Here you can learn how Google is interpreting your Canonical URLs.

Technical SEO support from Liberty

So that’s canonicalisation 101 – what it is, why it’s important, and what you need to do to work around it.

If you have a specific technical problem that hasn’t quite been answered here, feel free to reach out to our team for a more detailed chat about your queries. Our technical SEO team would be happy to look into your issues and propose ongoing solutions.