Canonical URL

A canonical URL is set with a link rel=canonical tag or an HTTP Link header. It points to the preferred URL for that content.

Small sites create duplicates without noticing: UTM parameters, uppercase paths, trailing slashes, sort and filter pages, http and https, with and without www. Each can split link equity and impressions across many URLs.

A clean canonical helps one page rank and get clicks. It also reduces crawl waste and weird metrics caused by near-identical pages competing with each other.

1. 1

   Pick the preferred URL format

   Decide on https, www or not, trailing slash or not, lowercase paths. Example: https://yourproduct.com/guides/getting-started/.

2. 2

   Add rel=canonical on the page

   In the head, link to the preferred URL. Example: /guides/getting-started?utm_source=newsletter should canonical to /guides/getting-started/.

3. 3

   Use redirects for true duplicates

   301 redirect http to https, non-www to www, and uppercase to lowercase where needed. Canonical is not a substitute for redirects on exact duplicates.

4. 4

   Avoid cross-page canonicals for different content

   Only point to a different URL when content is the same or a close duplicate. Variants like colour or pagination often need their own URLs with self-canonicals.

<link rel="canonical" href="https://yourproduct.com/guides/getting-started/">

• View source on the page and find link rel="canonical". Confirm it is absolute, matches https, host, path and trailing slash choices.
• If you set it via headers, fetch the URL with curl -I or your server logs and check the Link: <...>; rel="canonical" header.
• In Search Console, use URL Inspection to see the Google-selected canonical and the user-declared canonical. They should usually match.
• In the Page indexing report, watch statuses. “Alternate page with proper canonical tag” means Google found a canonical to a different URL and agreed, so this URL is intentionally out of the index. It is only a problem when the canonical is wrong.
• Track impressions and clicks for the canonical URL in the Performance report. Remember: impressions count when your link appears on a loaded results page, and the query table omits rare queries, so totals will differ.

1. 1

   Make every indexable page self-canonical

   /pricing should canonical to https://yourproduct.com/pricing/.

2. 2

   Canonical from parameter versions to clean URLs

   /pricing?ref=twitter and /pricing?utm_source=newsletter should canonical to /pricing/.

3. 3

   Handle pagination and facets with care

   Let /blog/page/2/ self-canonical. For filter pages that change the list but not the detail, consider noindex or block crawling rather than canonicals to page 1.

4. 4

   Keep canonicals consistent with redirects and hreflang

   Do not canonical to a URL that 301s, 404s, is noindexed, or is disallowed in robots.txt. Hreflang alternates should each self-canonical.

5. 5

   Audit regularly

   Crawl the site after deploys. Check that templates print the right canonical on all states: with and without trailing slash, pagination, sort, and login banners.

• Pointing every page’s canonical to the homepage. Fix: self-canonical each unique page.
• Mixing http and https or www and non-www between canonical and live URL. Fix: pick one, redirect the rest, match the canonical.
• Relative or malformed canonicals. Fix: use absolute URLs with the correct case and trailing slash.
• Multiple canonicals from tags and headers. Fix: send only one signal, remove duplicates.
• Canonical to a non-200 or blocked page. Fix: ensure the canonical URL returns 200 and is not noindex or robots.txt disallowed.
• Canonical used as a soft redirect. Fix: if the content moved, 301 redirect instead.
• Expecting Google to obey a bad canonical. As of 2026, Google treats it as a hint. Fix the underlying duplication so the hint makes sense.