Canonical URL
Ankit Agarwal · Head of Marketing
A canonical URL is the preferred address of a page that search engines index and show when the same content exists at several URLs. Google weighs many signals.
What is Canonical URL?
A canonical URL is the single preferred address for a piece of content that search engines index and display in results when that content is reachable at more than one URL. For example, example.com/pricing, example.com/pricing?ref=nav and http://www.example.com/pricing might show the same page; only one should be the canonical.
Site owners can suggest a canonical, but search engines make the final choice. Google calls this “Google-selected canonical”, as opposed to the “user-declared canonical” you specify. Ranking signals such as links are consolidated to the chosen URL, so getting it right affects which URL ranks and how authority is distributed.
How it works
Google groups duplicate pages and picks one representative using signals including:
| Signal | Strength |
|---|---|
| Redirects | Strong |
| rel=canonical tag or header | Strong |
| Sitemap inclusion | Weak |
| Internal and external links | Supporting |
| HTTPS over HTTP | Supporting |
To control the canonical URL:
- Decide the preferred URL format (HTTPS, www or not, trailing slash or not).
- Redirect obvious duplicates such as HTTP to HTTPS.
- Add self-referencing canonical tags on every indexable page.
- Link internally only to canonical URLs.
- List only canonical URLs in XML sitemaps.
- Verify with URL Inspection.
Examples
- A B2B SaaS company finds Google indexing /features/ with a trailing slash while its canonicals declare /features. Internal links used the slash version. Updating navigation links aligns Google’s choice.
- A cybersecurity blog republishes posts on Medium without a canonical back to the original. In some cases the copy ranks instead. The team adds canonical references where the platform supports them.
- An e-commerce category reachable via several filter combinations declares the unfiltered category as canonical, and Google consolidates signals there.
Best practices
- Be consistent everywhere: links, sitemaps, hreflang, structured data and canonicals should use the same URL.
- Monitor the Page indexing report for “Duplicate, Google chose different canonical than user”.
- Treat pages that are not true duplicates separately; canonicals only work for equivalent content.
- Document URL conventions for developers and content editors.
Common mistakes
- Declaring a canonical but linking internally to a different version.
- Listing non-canonical URLs in sitemaps.
- Using canonicals across different languages instead of hreflang.
Canonical URL and AI search
AI crawlers and engines that ground answers in web pages also benefit from one clear URL per piece of content. Duplicate versions split signals and can cause an outdated or parameterized URL to be cited. See how AI engines cite sources.
Related terms
Sources
Frequently asked questions
What is the difference between a canonical URL and a canonical tag?
The canonical URL is the preferred address itself. The canonical tag is one way of telling search engines which URL you prefer. Redirects, sitemaps and internal links are other signals. Google decides the canonical URL using all of them. Consistency across signals matters most.
How can I see which canonical Google chose?
Use the URL Inspection tool in Google Search Console. It shows the user-declared canonical and the Google-selected canonical. The Page indexing report also lists pages marked as duplicates where Google chose a different canonical than the one declared. Check key templates after releases.
Why did Google choose a different canonical than mine?
Usually because signals conflict. Internal links may point to another version, the sitemap may list a different URL, the declared canonical may redirect or be blocked, or the pages may not be close enough duplicates for Google to accept the hint.
