Canonical URLs: What They Do and How to Use Them

Canonical link signals for similar web pages

What does a canonical URL mean?

A canonical URL is the preferred address for a page when several URLs have duplicate or very similar main content. The rel="canonical" link element tells search engines which version you prefer to represent that content.

A canonical is a signal, not a command. Google considers it alongside other signals and may select a different URL if it considers another page a better representative.

Add a canonical link

Place one canonical link in the document <head>. Use the complete preferred URL, including the scheme and domain:

<link rel="canonical" href="https://example.com/guides/html/">

The preferred page can include a self-referencing canonical. Duplicate or alternate URLs can point to that same preferred address.

Choose the preferred URL

  • Use the canonical URL that you want people to share and that returns the final page successfully.
  • Keep internal links and your sitemap consistent with that preferred URL.
  • Use canonicals for duplicate or very similar pages, not as a way to consolidate unrelated pages.
  • Redirect duplicate URLs when they no longer need to remain available to visitors.

Common canonical mistakes

  • Do not assume the tag guarantees indexing or rankings; search engines can choose another canonical.
  • Do not block a duplicate URL from crawling with robots.txt if you need the crawler to see its canonical link.
  • A canonical tag does not secure a page or prevent people from visiting it.
  • Responsive design serves the same URL to all devices and avoids separate mobile URL signals. If a site uses separate mobile and desktop URLs, check the current search engine guidance for that setup.
  • Do not use canonical tags to join distinct pages in a series. Give each paginated page its own URL and crawlable links to the other pages.

What about paginated pages?

Use normal links so people and crawlers can move between pages in a series. Google no longer uses rel="next" and rel="prev" as indexing signals. Do not canonicalize every page in a series to page one when each page has distinct content.

For details, read Google Search Central’s guides to canonicalization and pagination.