Canonical tag

The canonical tag: An essential helper in the world of SEO

In the complex world of search engine marketing, the canonical tag, also known as ‘rel=canonical’, is a crucial tool for webmasters and SEO experts. This special HTML link tag is used to identify the preferred or “canonical” version of a web page. Its correct application plays a critical role, especially when it comes to dealing with duplicate content – a common problem that can negatively affect the visibility of a website in search results. If content on a website is accessible under several URLs, these different URLs can be grouped using a canonical tag so that there are no problems with duplicate content for Google, as thanks to the canonical tag it is always clear which is the original URL of the content.

The challenge of duplicate content

Duplicate content occurs when several URLs of a website have the same or very similar content. This can be caused by URL variants, session IDs or print versions of pages, among other things. Search engines such as Google are then faced with the dilemma of deciding which version of the content should be represented in the search results. Without clear instructions, this could lead to a fragmentation of search rankings and reduced visibility.

The solution with canonical tags

The canonical tag solves this problem elegantly by showing search engines the preferred URL for the content. By defining a canonical URL, it is made clear which version the content should represent. Search engines follow this advice by considering other pages with similar content as duplicates and generally do not display them in the search results. This not only prevents SEO problems caused by duplicate content, but also helps to consolidate link equity, as all links pointing to the duplicate pages are redirected to the canonical page.

Implementation and best practices

To use the canonical tag effectively, there are a few best practices to follow:

  1. Clarity in implementation: Ensure that the canonical tag is clearly and consistently stated on the preferred URL of each page. Inconsistencies can impair the effectiveness of the tag and lead to confusion for search engines.
  2. Avoidance with pagination: For paginated content (e.g. articles that are spread over several pages), the use of rel="next" and rel="prev" tags should be preferred instead of canonical tags. These indicate the order of the pages and help search engines to understand the structure of the paginated content.
  3. Careful combination with other tags: The use of canonical tags in combination with other meta tags such as noindex or nofollow should be avoided. Such combinations can send contradictory signals to search engines and potentially have a negative impact on the indexing and ranking of pages.
  4. Monitoring and adjustment: Regularly monitor the impact of your canonical tags using tools such as Google Search Console. Adjustments may be necessary if the structure of the website or the content of the pages changes.


The canonical tag is not just a technical tool; it is a fundamental component of a well-thought-out SEO strategy. Its proper use can significantly help to increase the effectiveness of search engine optimization by improving the clarity of content presentation and ensuring that valuable SEO resources are focused on the desired page. In a digital landscape characterized by content overload, the canonical tag provides a necessary guideline for search engines to correctly evaluate and reward the relevance and authority of web content.