Canonical Tag Checker
Find every canonical tag and Link header on a page and check it is absolute, self-referencing and free of conflicts.
Check a page's canonical tag
Redirects are followed; the canonical is compared with the final URL character for character.
What the Canonical Tag Checker does
A canonical tag tells search engines which URL is the master copy of a page when the same content is reachable at several addresses: with and without a trailing slash, with tracking parameters, over http and https, on a mobile subdomain, or on a partner site that republishes your article. Get it right and all those variants pool their signals into one URL. Get it wrong and a whole section of a site can quietly point at the wrong page, or at a page that redirects, or at nothing search engines accept.
This checker fetches the URL, follows redirects to the final address, and collects every canonical declaration: <link rel="canonical"> tags in the HTML and rel="canonical" entries in the HTTP Link header, which servers and CDNs sometimes add without the site owner knowing. Each one is resolved to an absolute URL and compared with the final page URL, so you can see whether the page points at itself, at another page on the site, or at another domain.
The verdict is the summary: good when there is exactly one absolute self-referencing canonical, a warning for relative URLs, duplicates or a scheme mismatch, and a fail for conflicting values or a tag placed in <body>, both of which make Google ignore the hint entirely.
Step by step
- 01Enter the page URL. Use the address visitors actually reach, including any trailing slash.
- 02Click Check. Redirects are followed and the final URL is what the canonical is compared with.
- 03Read the verdict, then the table of every canonical found with its source (HTML or header).
- 04If the page points elsewhere, open that target and check it points at itself; canonical chains waste crawl budget.
- 05Repeat on a page with a query string to confirm the parameter version canonicalises back to the clean URL.
Common questions
Yes, it is the safest default. It stops tracking parameters, uppercase variants and alternate hostnames from being indexed as separate pages, and it costs nothing. Only pages that are true duplicates of another URL should point somewhere else.
The comparison is exact on path and query, apart from host and scheme case. The usual culprits are a trailing slash on one side and not the other, http versus https, or www versus the bare domain. Each of those is a different URL to Google, so the canonical should match the final URL character for character.
A Link: <url>; rel="canonical" response header does the same job as the HTML tag and is the only option for files that have no HTML, such as PDFs. Some CDNs and SEO plugins add one automatically; if it disagrees with the tag in your HTML, you have a conflict and Google ignores both.
Yes. Cross-domain canonicals are the right way to republish an article on a partner site while keeping the ranking on the original. The tool flags them as informational so you notice them, since on your own site they usually mean a copied template from another project.
Keep checking
Meta Tag Analyzer
Check a page's title, meta description, canonical, robots, viewport, Open Graph and Twitter tags with a 0-100 score.
Free toolOn-Page SEO Checker
Audit a page's title, headings, word count, image alt text, canonical, links, schema and speed with a 0-100 score.
Free toolRedirect Checker
Trace a URL's redirect chain hop by hop, spot loops, meta refresh and JS redirects, and compare the http, https and www variants.
Free toolHreflang Checker
List a page's hreflang tags, validate the codes, check x-default and self-reference, and confirm alternates link back.
Free toolRobots.txt Tester
Fetch a site's robots.txt and test whether a path is allowed or blocked for Googlebot or any user agent, with the matching rule.
Want these fixes done for you?
Our team runs the audit, makes the changes and reports the result.