Canonical tags are nothing new. They’ve been around since 2009—the best part of a decade.
Looking to learn what canonical tags are, and how to use them to avoid dreaded duplicate content issues?
Google, Microsoft, and Yahoo united to create them. Their aim? To provide website owners with a way to solve duplicate content issues quickly and easily.
Canonical tags(rel=canonical) – We have often heard this term in on-page SEO. But to know more about it, let us discuss the canonical tags and their application in SEO
What is a canonical tag?
Canonical tags (rel=“canonical”) are a snippet of HTML code that defines the main version for duplicate, near-duplicate and similar pages. In other words, if you have the same or similar content available under different URLs, you can use canonical tags to specify which version is the main one and thus, should be indexed.
Sometimes referred to as “rel=canonical,” canonical tags tell search engines that a given URL is the master copy or authoritative source for a piece of content. If there are multiple versions of the same piece of content at different URLs, the canonical tag informs search engines which one is the primary source. The canonical tag appears in the HTML head of your page.
What do canonical tags look like?
<link rel=“canonical” href=“https://example.com/sample-page/” />
Here’s what each part of Canonical tags use simple and consistent syntax, and are placed within the <head> section of that code means in plain English:
- link rel=“canonical”: The link in this tag is the master (canonical) version of this page.
- href=“https://example.com/sample-page/”: The canonical version can be found at this URL.
Why are canonical tags important for SEO?
Google doesn’t like duplicate content. It makes it harder for them to choose:
- Which version of a page to index (they’ll only index one!)
- Which version of a page to rank for relevant queries.
- Whether they should consolidate “link equity” on one page, or split it between multiple versions.
Too much duplicate content can also affect your “crawl budget.” That means Google may end up wasting time crawling multiple versions of the same page instead of discovering other important content on your website.
So then, what is a canonical link? A canonical link is a URL that is chosen as the ‘master’ URL for a set of duplicate pages.
In Google’s own words:
A canonical URL is the URL of the page that Google thinks is most representative of a set of duplicate pages on your site.
— Google Search Console Help
You can indicate your preferred canonical URL. However, Google may choose a different page than you do for various reasons.
That said, in most instances, when set correctly, it will be your specified URL that is chosen as the canonical.
Put simply, canonical URLs dictate which page will usually (except in the case where a duplicate is explicitly better suited for a user, let’s say a mobile-specific version) be shown in the search results.
The canonical URL of a page can be on a different domain.
When are Canonical URLs necessary?
The previous example of the same content being at https://www.hubspot.com and https://hubspot.com is just one of the situations in which it is important to include a canonical URL. Each of the following situations is a commonly occurring instance of when you’ll want to make sure you’ve added a canonical URL:
URLs that Identify Variations of the Same Product
Especially on e-commerce platforms, it’s quite common for URLs to adjust depending upon the specifics of the product that a customer is looking at. For example, let’s say you’re selling dog toys, and have a popular chew toy that comes in three separate sizes and has color options as well. The main page for that product may be www.example.com/product, but you likely also have page URLs like www.example.com/product?size=large&color=blue.
Mobile-Specific URLs, Such as AMP Pages or a Mobile-Specific Subdomain
Creating content with mobile in mind is a marketing must — just be sure to remember to set your canonical URLs when you have pages that are specific to mobile but have the same content as a page on the desktop version of your website. For AMP pages specifically, Google also provides detailed guidelines on how to correctly differentiate your Accelerated Mobile Page from your standard webpage.
Region or Country-Specific URLs
Geotargeting is another great way to cater your content to your viewers based upon where they live. If you do this by adding a regional slug or using a regional subdomain (e.g. https://www.example.com/fi/page or https://de.example.com), you’ll want to make sure these region-specific pages point back to the master version of the page.
It’s important to note that if you’re translating your page (for example you have the master version in English and have another version that’s entirely in Mandarin), this wouldn’t be a case of duplicate content. When it comes to region-specific content, you’ll want to include the canonical tag if most of the on-page content is the same and in the same language.
Most CMS platforms do this automatically, but it’s important to not overlook it. When you create a page, you can set it as its own canonical URL. This is known as a “self-referential canonical URL.” The usefulness of self-referential canonical tags has been widely debated until recently when Google confirmed that this can help your pages perform well in search results.
What is a cross-domain canonical tag?
A canonical tag (also known as a “rel=canonical” tag) is a tried-and-true method of letting online search engines know that a specific URL represents the “master copy” of a website page. Implementing the canonical tag can prevent problems that are typically caused when identical or “duplicate” content appears on multiple URLs. Essentially, the canonical tag notifies search engines which version of a URL you want to appear in its search results.
In addition to negatively impacting your SEO rankings, duplicate content can cause some other pretty serious SEO problems if not addressed swiftly, properly, and thoroughly. When a search engine “crawls” multiple URLs with identical (or nearly identical) content, several of these SEO problems can unfold.
Rel=canonical is a powerful tool in an SEO toolbox. Especially for larger sites, the process of canonicalization can be very important and lead to major SEO improvements. But like with any power tool, you should use it wisely as it’s easy to cut yourself. I hope this guide has helped you gain an understanding of this powerful tool and how (and when) you can use it.