Canonical URL: Definition and use for SEO

Canonical URL, canonical tag, canonical rel, what do all these terms mean and how can you use the canonical URL to improve your search engine optimization and correct duplicate content problems?

That’s what we will see in this guide!

Working with the canonical tag belongs in every reasonable SEO action plan. You can learn more in my blog post about it.

Canonical URL: Definition: Definition

The canonical URL should be used to remind search engines that, among a number of similar sites, this is the site they should consider.

The terms “canonical tag”, “meta canonical” or “rel canonical” are often found on the Internet. Although all these terms are imprecise, they all refer to the same thing: the canonical URL.

Canonical URL: Definition Google

What is the purpose of the canonical URL?

One of the main problems of search engines is the management of the many duplicate contents that exist on the Internet.

Indeed, registering pages in their database requires a lot of storage space and is therefore very expensive.

Therefore, when a search engine encounters a page that is similar to another one, it must choose which one to store in its index (i.e. its database) in order not to overload its servers unnecessarily.

This is where the canonical URL comes in: it tells the search engine which is the original page it should take into account.

All pages with a canonical URL that is different from their own URL are then ignored by search engines.

Take a look at Google’s representation of canonical links:

How to add a canonical URL in HTML?

To add a canonical URL to your page, simply add the following code between the and tags:

<link rel=”kanonisch” href=”https://www.meineseite.com/url-orginalseite.html”>

Canonical URLs: a solution for problems with duplicate content

Search engines have created the canonical URL to solve the problem of duplicate content.

Here are some examples of cases where it can be useful to add a canonical URL to your pages.

Display the category in URLs.

On e-commerce sites, it is not uncommon for the name of the category in which a product is found to appear in the product page URL.

The problem is that if you decide to display your product in two different categories, it will generate two separate URLs displaying the same product page, then we are dealing with a typical case of duplicate content.

If you need more information about product pages, you will find it here.

By adding a “canonical URL” to your pages, you tell Google which is the preferred page to appear in search results.

Filter and sorting systems

Kanonische URL für Filtersysteme

This type of duplicate content appears in online shops and also on all other websites that display lists with sorting or filtering functions.

As soon as you generate different URLs with appropriate filters and the selected sequence, there is a risk of duplicate content.

Even if the pages are not completely identical, only the order of the elements changes.

Your pages will then be too similar for Google, so Google will select one version and ignore the others.

Instead of running the risk of letting Google choose a version of your page that doesn’t work well, it’s better to use the canonical URL to tell it which one you’d rather have included in its index.

The canonical URL to protect against content theft.

Another use of the canonical URL, which is not very well known but still very practical, is to partially protect against content theft.

Unfortunately, on the Internet, it is common for your content to be stolen and if that hasn’t happened to you yet, don’t worry, this danger is unlikely to last much longer.

The canonical URL will not protect you from all content theft techniques, but it will greatly reduce the impact of the most basic methods of robot automatic theft.

In fact, a large number of pages can be automatically detected, copied, and pasted into another website using a very easy-to-code script.

Because these robots are very simple, they copy all the HTML code of your page and integrate the canonical URL contained in it into their own website.

This explicitly instructs Google not to consider the page you just copied and to leave the original (i.e. your website) in the index.

If you use canonical tags on your pages, the robots will copy them as well. Therefore, Google ignores the stolen pages, thus avoiding problems with duplicate content.

Difference between 301 redirection and canonical URL?

From a search engine perspective, the canonical URL and the 301 redirect have more or less the same role.

They instruct the machine to ignore one page in favor of another.

The ignored page is therefore not registered in the index of the search engine and the popularity of the links pointing to it is transferred to the original page.

For users, however, it is quite different.

In fact, the 301 redirection redirects both search engines and users from the old page to the new page, while the canonical URL only addresses the search engines.

If you use canonical URLs instead of redirects, users are not redirected.

It’s important that you understand this difference, because then you’ll know how to use 301 redirects or canonical URLs intelligently.

You should use 301 Redirects when a page no longer exists and needs to be redirected to a new URL.

So again, you should add canonical URLs to pages that are useful to your visitors but should be ignored by search engines.

Are you looking for someone to solve problems with duplicate content for you? Please contact me, I am at your disposal.

You may also like...