Understanding Canonicalization: What It Is and Why It Matters

Have you ever wondered what happens when you type in a URL with or without the “www” before it? Or perhaps, you have encountered issues where you created two web pages with the same content but different URLs, only to find out that there’s a problem with indexing and ranking on search engines?

Understanding canonicalization is an essential factor in website optimization that many website owners often overlook. Canonicalization refers to the process of standardizing URLs to prevent multiple URLs from displaying the same content on your website, which can negatively impact your website’s SEO performance.

What is Canonicalization, and Why Does it Matter

Simply put, canonicalization is the process of specifying a preferred URL for indexing and ranking in search engines. Search engines like Google crawl the web to index pages and content. But oftentimes, different URLs can lead to the same page, and this can cause duplicate content issues that can hinder your website’s search engine’s visibility.

For instance, let’s say you have an e-commerce website that has a product page for a new laptop. The product page’s original URL is yourwebsite.com/products/new-laptop. However, in other instances, the same page is accessed through several URLs with different parameters such as yourwebsite.com/products/new-laptop?color=red, yourwebsite.com/products/new-laptop?size=15, and yourwebsite.com/products/new-laptop?price=500. These URLs’ variations can cause duplicate content issues for search engines, and they may not be able to determine which one to index and return as search results.

Canonicalization helps avoid this problem by indicating which version of the URL should be indexed and ranked. A canonical URL is the preferred version of a URL that Canonicalization you want search engines to display and credit with authority. This way, search engines can identify the original page and rank it higher in search results while avoiding duplicate content issues.

Types of Canonicalization

There are several ways to specify a canonical URL for your web pages, depending on your website setup and content management system. Here are some of the most common methods:

1. HTTP versus HTTPS

If your website is accessible via both HTTP and HTTPS protocols, you can set a preferred version to manage and monitor your site’s activity better. For instance, HTTPS is the more secure version of HTTP, and it encrypts data transmitted between users and servers. If you have implemented SSL/TLS certificates for your site, you can use the HTTPS version as your canonical URL.

2. www versus non-www

When you type in a web address, it can begin with “www” or not. This may seem like a minor difference, but it can affect your website’s backlinks, traffic, and page authority. You can set a preferred version of your URL by redirecting one version to the other using a 301 redirect. This way, search engines can identify the original page and avoid duplicate content.

3. Similar pages and URL variations

When your website has several similar pages, such as product pages with different colors, sizes, or prices, you can set a preferred version for indexing, ranking, and displaying to users. You can use the rel=canonical tag in HTML to point search engines to the preferred URL, and also to let them know which pages to omit from search results.

Why Canonicalization Matters

Canonicalization may not seem like a critical aspect of optimizing your website, but it plays a significant role in maintaining your website’s search engine visibility and authority. Here are a few reasons why canonicalization matters:

1. Eliminates Duplicate Content

When search engines crawl your website, they index pages that they consider useful and valuable to users. When a search engine encounters several similar pages with different URLs, it may not be able to identify the original version and may result in duplicate content issues. Setting a preferred canonical URL ensures that search engines index and rank the original and useful version of your web page, thus avoiding duplicate content problems.

2. Improves Search Engine Visibility

When your website has several pages with similar content, it might dilute your website’s page authority and ranking performance. Canonicalization helps consolidate your website’s pages by directing search engines to the preferred version, which reinforces your pages’ quality and authority.

3. Enhances User Experience

When users type in a URL, they expect it to be directed to the right webpage without any redirects or errors. With canonicalization, you can ensure that users visiting your website via different URLs can land on the correct and preferred version.


Canonicalization plays a critical role in managing and optimizing your website for search engines and user experience. By setting a preferred URL, you can consolidate your website’s pages, avoid duplicate content, enhance your website’s page authority and ranking, and improve user experience. Canonicalization may seem like a minor detail, but it can have a huge impact on your website’s search engine optimization strategy.