Crawl and index controls
Canonical URL
Also called: rel=canonical
A canonical URL is the preferred address of a page when the same or very similar content is available at several URLs.
In plain words
Duplicates happen easily: tracking parameters, print versions, http and https, with and without www.
You tell Google which version you prefer. Google then decides which one to show.
Example
A shoe shop shows the same sneakers at /shoes/red-sneakers and at /sale/red-sneakers. It adds the canonical tag below to both pages, pointing to the first address.
<link rel="canonical" href="https://example.com/shoes/red-sneakers">Why it matters for AI search
Google calls redirects and rel="canonical" strong signals, and inclusion in a sitemap a weak one.
Google adds that these methods stack: using two or more increases the chance that your preferred URL is chosen.
Google also notes that duplicate content can waste crawling resources on URLs you don’t even care about.
What you can do
- Give every page a canonical tag pointing to its preferred URL; on a unique page, that is the page itself.
- Use redirects for URLs you no longer want at all.
- List only canonical URLs in your sitemap.
Often confused with
- Redirect
- A redirect sends visitors to another URL. A canonical tag keeps both URLs reachable and only states a preference.
Sources
Facts and sources last checked on 19 October 2026.
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