What is a Canonical URL?
A website has many URLs, but how does a search engine know which one to rank on top? Well, to clear this confusion, websites use a cannonical url such as rel="cannonical" in their html link to help search engines recognise it as the websites preferred version. This help in avoiding showing duplicate pages or content of the same kind. It boosts the SEO of a website, and helps the search engines in ranking it on top.
Look at the following URLs to understand how a product page can be accessible:
https://exampl .com/product
https://example.com/product?ref=123
https://example.com/product?sessionid=456
With the help of a canonical URL, you signal to the search engines that the one URL (e.g., https://example.com/product) is the authoritative or the main version. And all the others are the duplicate versions.
What is a Canonical Tag?
It is basically an HTML element that is used to show the cannonical URL for a web site. It is displayed like this (<link rel="canonical">). It is always placed in the <head> section of the HTML code. This way search engines can recognise the page that needs to be shown as the main page of a web.
Look at the following URLs to see how a canonical tag looks like in HTML:
html
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<link rel="canonical" href="https://example.com/product" />
This tag indicates that the cannonical URL is https://example.com/product this. Even if the same content is appearing on other URLs. A canonical URL is an important tool when it comes to managing the duplicate content issues on websites.
Importance of Rel=Canonical in SEO
The rel=canonical attribute is the most important component of the SEO strategy. Look at the following to understand why is it important:
1. Consolidates SEO Value
A canonical tag increases the SEO value of a webpage that has many URLs. With its help, search engines know and recognise which page is the main page of the web. It then shows and ranks it on top, and treats other URLs as duplicates.
2. Avoids Duplicate Content Issues
Without a canonical tag, search engines' algorithms become confused. It doesn't understand the difference between multiple URLs showing the same content. They can even penalize a site for duplicate content. But by using a canonical tag, you can indicate to them the preferred page they should index.
3. Optimizes Crawl Budget
By using a canonical tag, you can save the time and budget of search engines. Since they have limited time to crawl through your website, you can let them know through canonical tags which pages are important and relevant. This way search engines can easily rank them, and avoid all the duplicates.
4. Improves User Experience
Canonical tags also help the users in finding the right content of your website. They can find exactly what they are looking for in search results. This allows them to have a consistent and positive browsing experience.
5. Supports Content Syndication
When you share your content on other sites, then using a canonical tag can help the search engines track it back to its original source. I e. Your site. This way only your site gets the credit, recognition, and ranking for the content in search engines.
How to Spot a Canonical URL
You can easily spot a canonical URL if you know where to look for it. Some of the ways of finding it are as follows:
View Source Code
- First of all, open the webpage in your browser.
- Then press right-click and select "View Page Source."
There you can look for the <link rel="canonical"> tag in the <head> section. It will look like this:
html
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<link rel="canonical" href="https://example.com/canonical-page" />
Inspect with Browser Developer Tools
Use the browser tools like the Chrome DevTools:
- First, Right-click on the webpage and then select “Inspect.”
- Then check the <head> section for the canonical tag.
Use SEO Tools
There are tools like Screaming Frog, Ahrefs, or SEMrush which can automatically scan the site to search for canonical tags. They can then identify on their own which URLs are set as canonical.
Google Search Console
- Inspect a URL under the “URL inspection” tool in Google Search Console.
- Check the "Canonical URL" section to see which URL Google has chosen as the canonical version.
If you are unable to find a canonical tag in the HTML, then it means the page hasn't defined one. In such cases, search engines select a canonical tag for a website on their own.
SEO Considerations for Canonical URLs
It is important for a canonical URL to be implemented correctly. Otherwise, it can not maintain a strong SEO strategy for search engines. The following are some of the key considerations for implementing it correctly:
- Self-Referencing Canonical Tags
Even if your page has no duplicates, still always include a self-referencing canonical tag. This avoid confusion for the search engines. For example: (<link rel="canonical" href="current-page-URL" /> - Dynamic URL Management
Always use canonical tags to point to the clean and static version of the URLs. Especially on websites with dynamic parameters (e.g., session IDs, UTM tags). It helps in preventing the duplicates. - Cross-Domain Canonical Tags
If you share your content on other websites, then always make sure that that third-party site includes a canonical tag. This helps in pointing the content back to your original page. - Consistency Across HTTP and HTTPS
Make sure that the canonical tags consistently point to either the HTTP or HTTPS version of a page. It depends on which protocol your site is using. But for the most modern sites, the canonical should point to the HTTPS version. - Avoid Conflicting Signals
Never combine your canonical tags with "noindex" directives or 301 redirects. Otherwise, it will send mixed signals to the search engines. And by doing so, you can undermine the effectiveness of your canonical strategy. Their use will not be beneficial for your website. - Canonicalize Similar but Unique Content
If some pages on your web appear similar but have unique value, then you should use canonical tags sparingly. For example, use localized pages or category filters to avoid confusion.
When to Use a Canonical URL
Using canonical URLs is most beneficial when there is a need to manage duplicate or similar content on a website. Have a look at the following examples:
- Duplicate Content Across Multiple URLs
A canonical Url helps in differentiating the same content that appears on different URLs due to tracking parameters, session IDs, or sorting filters. For example:- https://example.com/product
- https://example.com/product?ref=affiliate
- Content Syndication
When you share your content with third-party websites, then adding a canonical tag can point it back to its original use. This way it's your site that gets the SEO credit. - Paginated Content
Canonical URLs help in combining different pages of the same content by tracking them back to the main page. For example, in the case of a series where similar content is spread across many pages, a canonical url is used to show the main page. But if each page has a different value, then add self- referencing canonical urls to show them individually. - Dynamic or Search Result Pages
It is a canonical tag that points to the main version of a page. In cases where dynamic URLs or search results generate duplicate content. For example, the use of filter parameters like ?color=blue or ?size=large. - Similar Product Pages
If there are many variants of a product available on an e-commerce site, such as different colours and sizes. But they are available on separate URLs, then the use of a canonical URL will point them back to the main product. - HTTP vs. HTTPS or www vs. non-www
If your site can be accessed via multiple protocols such as HTTP/ HTTPS or subdomains like www vs. non-www, then using canonical tags can be helpful in designating the preferred version.
