Canonical URL

A canonical URL is the one authoritative web address a page declares for itself, using a <link rel="canonical"> tag in the page's header:

<link rel="canonical" href="https://www.example.com/about">

Websites often serve the same content at several addresses (with and without www, with tracking parameters, and so on). The canonical URL tells search engines which of those copies to index and rank, so ranking signals are not split between duplicates.

A canonical tag is a strong signal, not a command: search engines weigh it alongside other evidence, such as internal links, redirects, and sitemap inclusion, and can choose a different page as canonical if those signals disagree with it.

Learn more

• Consolidate duplicate URLs - Google's guidance on canonicalization
• XML sitemap