What is a canonical URL?
A canonical URL is the address you mark as the preferred version when the same or very similar content can be reached through more than one URL. That is usually a rel="canonical" element in the HTML.
A canonical is a strong signal, not an order. Google may choose a different URL when other signals point that way.
A practical example
Suppose the same product has a normal product URL and another URL with a sort parameter. The second can point at the first. example.com is a made-up address here, not a customer.
The element belongs in the head. The target URL should be reachable and show the intended content, not an error page or a redirect.
<link rel="canonical" href="https://example.com/shoes/model-a">When do you use a canonical?
Do not point every page at the homepage. A unique page, if it has a canonical, points at itself.
- One product can be reached through several URL variants.
- Tracking parameters or filters create very similar pages.
- The same content is deliberately on different URLs and you have a preferred version.
Common mistakes
A canonical that targets a 404 or a redirect is a poor destination.
A canonical to URL A, while the sitemap and internal links emphasise URL B, makes the preference unclear.
A page for one city should not share a canonical with a page for another city when each has its own content and job.
A chain, or a loop where canonicals point at each other, makes the preference unclear.
Check it yourself
- Open the HTML and read the canonical element.
- Check that the target URL is reachable and shows the right content.
- Compare internal links and the sitemap with that preferred URL.
- In Search Console, when it is connected, see which URL Google selected.
Is a canonical the same as a redirect?
No. A redirect sends visitors and search engines to another address. A canonical usually leaves the page reachable and only states a preference. The element is not required, and it does not guarantee that Google picks your URL.