What is Canonical?

In HTML, the canonical meta tag is a value of the “rel” attribute whose purpose is to specify the preferred URL of a web page. It must be specified within a <link> tag in the header of the page (between <head> and </head>,) otherwise it will not be taken into account by search engines. An example of a canonical meta tag would be:

The address specified in the “href” attribute is the canonical or preferred URL. That is, it is the one that should be displayed in the address bar and, also, the one that will be indexed by search engines. That is why using the meta canonical in SEO is essential if you want your site to be well indexed.

Table of contents

1 I understand canonical URLs with examples
2 Canonical in Search Console

I understand canonical URLs with examples

Let’s suppose that the site we gave as an example is accessible through the following addresses:

https://www.mitiendaonline.com  https://mitiendaonline.com  https://www.mitiendaonline.com/index.php  https://mitiendaonline.com/index.php

All of them are valid and, at least if we follow common sense, there should be no problem with it. But in this case common sense is wrong: if you don’t declare a meta canonical, the SEO of your page could suffer.

1. Bad indexing

Search engine spiders (e.g. Google bot) will have to crawl each URL, even if they point to the same page. That’s time it takes for the search engine to index your site, and the possibility that Google thinks you have duplicate content. You can avoid all this by including a rel=canonical telling the search engine what your preferred URL is.

2. Unfriendly URL’s

Another reason to use the canonical meta tag in SEO is that, if you don’t specify it, the search engine will take care of it. And you may not like the result. Imagine that the address of your cleaning products catalog is located at:

https://mitiendaonline.com?categ=hogar&subcat=limpieza

But you want it to appear in a simpler and more organized way, like the following:

https://mitiendaonline.com/hogar/limpieza

The best way to get this last URL to appear in the browser address bar, and have Google display it instead of the previous one, is to define it as a canonical URL. If you pass on this, it is possible that the first URL will be the one displayed in the search engine result pages.

3. Difficulty in tracking metrics

Another great benefit of using a meta canonical is that it simplifies tracking metrics. This is very useful especially in online stores, when we need to track specific products or categories.

Canonical in Search Console

It is worth saying that in Search Console you can see how bad indexing is happening through the Index Coverage Status Report. This tells you which pages have been indexed and which have not, and how to fix it. Those not indexed appear in the Excluded section: if a certain page appears there for duplication reasons, you will notice it because one of the following reasons appears:

Duplicate: the user has not indicated any canonical version
Duplicate: Google has chosen a different canonical version than the user.
Duplicate page that is not HTML

This can be easily solved by adding rel=canonical to the page indicated in the report.