Start here#
Choose the URL you want search engines to represent. Then make the canonical tag, redirects, internal links and sitemap agree with that choice.
- Compare the declared canonical with the final live URL.
- Check whether alternative URLs are genuine duplicates before consolidating them.
- Inspect Google’s selected canonical and review any conflicting signals.
What a canonical URL is#
A canonical URL is the preferred representative of a duplicate or near-duplicate set. You can recommend it with a canonical link element in the page head:
<link rel="canonical" href="https://example.com/guides/wordpress-seo/" />The recommendation is strongest when the page, internal links, sitemap, redirects, and protocol all agree. It is not an instruction search engines must obey, so conflicting signals can lead them to choose a different representative.
The three canonical states worth understanding#
Self
The canonical points to the current preferred URL. This is the usual state for an original post, page, or product.
Other
The page recommends a different URL. This can be correct for a duplicate, variant, syndicated copy, or parameterised version.
Not declared
No canonical was found or reliably verified. That is a missing preference signal—not automatic proof that the page cannot be indexed.
Where duplicate URLs come from#
Publishing platforms can expose the same content through several paths. Common examples include HTTP and HTTPS, www and non-www hostnames, trailing-slash variations, tracking parameters, print views, product variations, faceted shop URLs, attachment pages, and syndicated copies.
You do not need to canonicalise every remotely similar page together. The destination should be genuinely equivalent and useful as the single search result.
Distinct search intent or meaning usually deserves its own URL and self-reference.
A canonical implementation checklist#
- Choose one permanent preferred URL.Use the final HTTPS hostname and the exact path format your site serves.
- Use one canonical declaration.Multiple SEO plugins or theme output can create conflicting canonical tags.
- Point directly to a live destination.Avoid redirected, broken, blocked, or noindexed canonical targets.
- Align internal links and sitemaps.Link to and list the preferred version instead of asking crawlers to reconcile mixed addresses.
- Use redirects when the duplicate should disappear.A permanent redirect is clearer than keeping an unnecessary alternative live.
- Do not confuse canonical with noindex.A canonical consolidates equivalents; noindex asks for exclusion. They solve different problems.
Troubleshooting canonicals in WordPress#
View the rendered source—not only the editor setting—and search for rel="canonical". Confirm there is one declaration and that it matches the final URL.
If it does not, check your SEO plugin, theme hooks, multilingual or e-commerce extensions, custom filters, and cached HTML.
A self-reference is reassuring, an “Other” state deserves context, and “Not declared” calls for review. None of these alone proves whether a URL is currently in Google.
For the surrounding technical checks, read the IndexToast indexability guide.
Sources and further reading#
Official documentation for the checks explained in this guide.
Choose your next step#
Follow the guide that matches your next decision.
Questions, answered#
What is a canonical URL?
A canonical URL is the preferred representative of a page when the same or very similar content is available at more than one address.
Should every page have a self-referencing canonical?
For most indexable posts, pages, and products, a self-referencing canonical is a useful clear signal. Intentional duplicates should point to the preferred equivalent URL.
Is a canonical tag a guarantee?
No. It is a strong preference signal, but search engines can choose a different canonical when other signals disagree.
Should a canonical point to a redirect or 404 page?
No. Point it directly to a live, indexable preferred URL that returns the intended content.