Canonical URL

How Canonical URLs Work

The basic purpose of a canonical URL is to ensure that search engines index the preferred version of a webpage, while also allowing non-preferred duplicate pages to exist without negatively impacting the overall SEO. For instance, you may have two different URLs for similar content:

example.com/shoes/red

example.com/shop/red-shoes

Although these two pages may display identical or very similar content, search engines could see them as separate pages, which might dilute your SEO efforts. By adding a canonical tag to one of the pages, you tell search engines that one URL should be prioritised for indexing and ranking.

For the example above, you might choose the first URL (example.com/shoes/red) as the canonical page. The HTML code for this would look like:

This tag directs search engines to treat https://example.com/shoes/red as the primary page, even if the content on https://example.com/shop/red-shoes is identical or similar.

Benefits of Canonical URLs

Improved SEO Performance: By consolidating ranking signals to the canonical page, you avoid the risk of having your SEO efforts diluted across multiple pages. This can lead to better rankings for the preferred page.

Prevents Duplicate Content Penalties: Search engines, particularly Google, may penalise websites for duplicate content. Canonical URLs inform search engines which content version should be indexed, preventing any penalties for perceived content duplication.

User Experience Optimisation: A well-implemented canonical URL helps prevent confusion for users who may encounter multiple versions of the same content. It ensures they are directed to the correct page.

Link Equity Consolidation: Links pointing to various duplicate pages are all consolidated to the canonical version. This strengthens the overall authority and ranking potential of the chosen page.

When to Use Canonical URLs

Best Practices for Using Canonical URLs

Use Absolute URLs: Always specify the full URL in the canonical tag (e.g., https://example.com/shoes/red) rather than relative URLs.

Apply Canonicals to All Duplicate Pages: If there are multiple pages with duplicate or very similar content, implement canonical tags on all of them pointing to the preferred version.

Canonicalise Across Domains: You can use canonical tags to indicate the preferred content when the same content appears on different domains, such as syndicated content or partner sites.

Do Not Use Canonicals for Content You Want to Rank: Canonical tags should only be used on content you do not want to rank separately. If you want to rank multiple pages with similar content (e.g., different product colours), do not use canonical tags.

Check for Errors: Regularly audit your website to ensure that canonical tags are properly implemented and not leading to incorrect pages.

Common Misconceptions About Canonical URLs

Canonical URLs don’t redirect pages: A canonical tag does not perform a redirect. It only signals to search engines which page to prioritise for indexing. If you need to redirect users from duplicate pages, use 301 redirects instead.

Canonical URLs don’t prevent duplication: The canonical tag tells search engines which page should be considered the “authoritative” one, but it doesn’t remove the duplicate content itself. Proper site structure and URL management are still important.

Conclusion

Canonical URLs are a powerful tool for maintaining healthy SEO on websites with duplicate content. They allow website owners to consolidate rankings and prevent penalties associated with duplicate content. By using the canonical tag effectively, you can ensure that your content is indexed correctly, ultimately improving your website’s visibility in search engine results pages (SERPs).