A single page can be accessible by multiple different URLs; however it will result in Google interpreting the different URLs as duplicate versions of the same page. Google will typically choose one of these URLs as a master copy of the page and crawl that. All other duplicate URLs will be crawled far less often.
This is also the case with different pages with similar or identical content. Duplicate content issues can have a significant impact on the SEO health of a website and the overall quality of site traffic.
Failing to explicitly state which page is the master copy will lead Google to make the decision for you or they may decide to treat both pages as equal if the content is deemed distinctive enough.
What is a Canonical URL
A canonical url is a way of specifying to search engines which page among a set of similar or duplicate pages is the main and or preferred version of a web page.
There are several different ways of creating a canonical url some of which will be discussed further down the post; perhaps the most common is using the rel=”canonical” link element in the HTML code of a web page. This canonical tag is used to prevent duplicate content issues from occurring on your site and to tell search engines which url/page should be indexed
The pages on your site don’t necessarily have to be identical or even on the same domain to be grouped together as duplicate content.
How Google Chooses Which URL is Canonical
Google’s algorithms use various signals, including rel=”canonical” link element, HTTP headers, sitemap files, and link structure, to determine which URL to index as the canonical URL for a given web page.
As previously discussed, when a web page includes a rel=”canonical” link element, Google considers the URL to be the preferred one for the page. This link element tells Google that the web page has identical or similar content to another URL and that the specified URL should be considered the primary URL. If the web server sends HTTP headers indicating the preferred URL, Google uses that information to determine the canonical URL.
Additionally, if a web page is listed in a sitemap file with a specific URL, Google uses that URL as the preferred URL for indexing the page. Google also uses the link structure of a website to determine the preferred URL for a web page. For instance, if most of the links to a page point to one specific URL, Google considers that URL to be the preferred one.
It’s important to note that Google may choose a different URL as the canonical URL than the one you as a website owner may specify. This can happen if Google determines that another URL is a better representation of the content of the web page. In such cases, Google may ignore the rel=”canonical” link element or other signals and index a different URL.
Understanding how Google determines the canonical URL for a web page is essential for website owners and SEO professionals. By optimising the website’s link structure, including rel=”canonical” link elements, and submitting sitemap files, website owners can help Google identify the preferred URL for their web pages.
Finding the Canonical URL for a Web Page
Now that you know how Google chooses the canonical for a web page; the next step is to discover whether Google has abided by your specified canonical tag and how to identify the canonical URL for a web page. Fortunately, there are several different approaches you can use to determine the canonical URL that search engines, particularly Google, recognise for a particular web page.
For example, there are free tools available to webmasters like Google Search Console that allows you to inspect URLs and discover the current index status of a specific url. It can be useful in checking whether or not Google is using the correct url as the canonical url and that there are no indexing or crawling issues.
A tool such as Google Search Console can be an easy and revealing way of assessing whether Google has respected the canonical URLs you may have set on your site. However, it is not necessary to use such tools to reach these results. You can view the cached version of a web page by simply searching for “cache:url” in Google. This will show the version of the page that Google has already indexed.
Google cache can be a useful tool but works best if used in conjunction with other tools; such as the previously mentioned Google Search Console to ensure that you have a clearer picture on your site’s performance and canonical tags. The reason for this is that Google cache doesn’t show a real-time version of a webpage, and its age depends on how frequently the page/site is crawled. As a result, it could be several days or weeks old and may not reflect the most current version of the page.
Why your site may have similar or duplicate pages
While you may believe that your website does not contain any duplicate content and that canonical tags are unnecessary, there are several reasons why similar or duplicate pages may exist, such as:
- Printer friendly versions of pages
- URLs with and without www
- URLs with different parameters or sorting options
- Different versions of the same pages for different countries or languages
- Mobile versions of pages
- HTTP and HTTPS versions of pages
- Sessions IDs or tracking parameters
- Mistakenly creating duplicate pages
- Copied content from other websites
However, by using appropriate canonical tags, duplicate pages shouldn’t confuse search engines or significantly impact your website’s SEO and performance.
Knowing this, it is important to consider implementing canonical tags as a part of your content strategy. As this will help to reduce the likelihood of future duplicate content issues and to ensure that ranking signals are consolidated on a single url.
The Importance of Selecting a Canonical URL
When it comes to optimising a website for search engines, choosing a canonical URL is an essential step that should not be overlooked. A canonical URL is a preferred URL that search engines use to index a web page, even if there are multiple versions of the page available. By selecting a canonical URL, you can prevent duplicate content issues, improve your website’s overall SEO, avoid penalties, and facilitate effective link building.
One of the primary reasons why you should choose a canonical URL; and that has already been discussed at length in this post, is to prevent duplicate content issues. When a website has multiple versions of the same page, search engines may have difficulty determining which version is the most relevant and should be displayed in search results. This can lead to the indexing of multiple versions of the same page, resulting in duplicate content. Duplicate content can negatively impact your website’s SEO, as it confuses search engines and thus needs to be accounted for in your content strategy. By specifying a preferred URL for a page, you help search engines avoid indexing multiple versions of the same page, and thus help prevent/minimise the risk of duplicate content issues.
Choosing a canonical URL can also help improve your website’s overall SEO. When search engines index multiple versions of a page, it can split the page’s ranking signals among the different versions. For example, incoming links and social signals may be split among multiple versions of the same page, resulting in lower ranking signals for each version. By choosing a canonical URL, you ensure that all ranking signals are consolidated on a single URL, which can improve your website’s overall SEO.
Another reason why choosing a canonical URL is important is to avoid penalties. Search engines may penalise websites with duplicate content, as it goes against their guidelines. By specifying a canonical URL, you can avoid penalties and maintain a clean, well-organised website. Penalty avoidance is essential to maintaining a good reputation with search engines, which in turn can positively impact your website’s ranking.
Facilitating effective link building is yet another reason why you should choose a canonical URL. When other websites link to your pages, it’s important to have a clear, preferred URL for each page. This makes it easier for others to link to your content and helps ensure that all incoming links are directed to the preferred URL. Effective link building is a critical part of SEO, and having a clear, preferred URL for each page can help facilitate this process.
In summary, choosing a canonical URL is a crucial step in maintaining a well-organised website that is optimised for search engines. By doing so, you can avoid duplicate content issues, improve your website’s SEO, avoid penalties, and facilitate effective link building. To select a canonical URL for a page, it’s important to consider factors such as the page’s content, its URL structure, and its incoming links. By selecting a canonical URL that accurately represents the content of the page, you can help ensure that search engines display the most relevant version of the page in search results.
It’s important to note that selecting a canonical URL is not a guarantee that search engines will only display that version of the page in search results. Search engines may still choose to display alternate versions of the page based on a number of different factors, such as the user’s location, device type, or search query. However, selecting a canonical URL is still an important step in optimising your website for search engines and should not be overlooked.
To ensure that your website is fully optimised for search engines, it’s important to regularly monitor your website’s indexed pages and ensure that search engines are correctly identifying the canonical URL for each page. By using tools such as Google Search Console and the URL Inspection tool, you can check the current index status of each page and make any necessary changes to the canonical URL. Regularly monitoring your website’s indexed pages, can help ensure that your website is well optimised for search engines and satisfies users’ search intent.
How to Specify a Canonical Page
Specifying a canonical URL for a web page can be a pretty simple process. It involves including a rel=”canonical” link element in the HTML code of the page. By ensuring that the link element is included in the head section of the HTML code and follows the example below you can successfully specify a canonical page.
<link rel=”canonical” href=”https://www.example.com/preferred-url/”>
There are a number of other methods you can use to specify a canonical page, some of which like redirects and sitemap inclusion have already been addressed in this post. The most effective method however, is typically the method above.
It’s important that you only specify one canonical URL per page. If you have multiple pages with similar content, you should specify a canonical URL for each page.
What to avoid
It is important to be mindful of the limitations and potential pitfalls of using a canonical URL, and to use it correctly to avoid negative impacts on your website’s SEO and user experience. For example, here are some things that you should try and avoid when specifying a canonical URL:
- Accidentally pointing a canonical URL to a non-existent page that returns a 404 error; for example, as a result of a spelling mistake within the canonical tag, can confuse search engines and hurt user experience as well as other SEO metrics.
- You must ensure that you avoid designating a canonical URL to a page with different content. Associating a canonical URL with a page that has content differing from the original page may lead to user confusion and can have adverse negative effects on your website’s credibility.
- As previously discussed, don’t specify multiple canonical URLs for a single page. Each page should only have one canonical URL; otherwise it is likely to confuse search engines and may lead search engine crawlers to completely ignore the canonical URLs you have set for the given page.
In conclusion, understanding how search engines determine the canonical URL for a web page is vital for website owners and SEO professionals. As correctly implementing canonicalisation is crucial for improving the overall SEO health of a website and in ensuring that search engines choose the correct URL for indexing a web page. The use of free tools such as Google Search Console can help to determine whether Google is using the correct URL as the canonical URL, and by optimising a website’s link structure, submitting sitemap files and using appropriate canonical tags, website owners can reduce the likelihood of future duplicate content issues and improve their website’s performance in search engine rankings.