Canonicalization is a method used to help prevent duplicate content issues and manage the indexing of URLs in search engines. Using canonicals appropriately can be hugely helpful for SEO.

Implementing the canonical tag link attribute “rel=canonical” is a signal to search engines about the preferred page for indexing, and will be followed in most cases when it is correctly implemented to an equivalent page.

The collected SEO Office Hours notes below provide detailed information and best practices (straight from Google’s own search experts) for using canonicals on your website.

Incorrect Google Caching Suggests a Different Canonical Has Been Chosen

January 9, 2018 Source

If the cached content from a different page is displayed on a page, this could be because Google has determined that the two pages are duplicates and has canonicalised one to the other.

You Can See Which Canonical Google Has Chosen in the New Search Console

January 9, 2018 Source

In the new Search Console you can select individual URLs which takes you to the info query showing you the canonical that Google has chosen.

Canonicals Are Chosen by Google Using XML Sitemap URLs

January 9, 2018 Source

XML sitemap URLs are used to help inform Google’s decision on which URL is chosen to be the canonical.

Mobile Pages Must be Canonicalised to their Desktop Equivalents

November 14, 2017 Source

If the desktop and mobile versions of a page both appear it means that Google doesn’t understand the connection between them. Make sure the mobile page has a canonical tag to the desktop page.

Rel Canonical Isn’t Required For Paginated Pages

November 3, 2017 Source

If pagination is added to a page with rel next and rel previous it isn�۪t necessary to add a rel canonical to the page itself but it’s good practice.

Content on Canonicalised Paginated Pages Will Be Lost

October 6, 2017 Source

Unique content and links on canonicalised paginated pages will be lost if Google accepts the canonical directive.

Update Internal Links to Canonical URLs

October 6, 2017 Source

Update internal links to canonical URLs to give Google a clean signal about which URL to index. If the canonical is accepted, any links to canonicalised URLs will be associated with the canonical URL.

Low Proportion of Indexed Pages Points to Technical Issue

September 22, 2017 Source

If a site has a low proportion of indexed pages, this usually points to a technical issue than a quality issue. Compare the site map index counts and index status report for differences. Try splitting up sitemap file , checking indexed pages using info: query, that rel canonicals match those in sitemap file, hreflang and internal linking. Also, uppercase, lowercase, trailing slashes all matter. Then check crawl stats to get idea of crawl rate and if it’s reasonable.

Align Linking & Rel Canonical If Want Particular Page Indexed

August 25, 2017 Source

Ensure internal links and rel canonical are pointing to preferred page to ensure you aren’t giving Google conflicting signals about which page should be indexed.

Related Topics

Crawling Indexing Crawl Budget Crawl Errors Crawl Rate Disallow Directives in Robots.txt Sitemaps Last Modified Nofollow Noindex RSS Fetch and Render