Canonical declarations
Read canonical links in HTML and HTTP headers.
Canonical Tag Checker
Enter a page URL. See its declared canonical and the fixes that need attention.
What we check
Understand the canonical declared by a page and its immediate destination.
Valid URLs
Resolve relative links and identify invalid or empty URLs.
Conflicting targets
Find duplicate declarations and different target URLs.
Target response
Check the destination’s HTTP status and redirects.
Indexing directives
Identify noindex on the source and target.
Canonical chains
Check whether the target declares another canonical or links back.
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Enter a page
Paste the URL of the page you want to inspect.
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Run the check
Read its declarations and check one different target.
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Review the findings
Fix confirmed errors, review warnings and download the report.
Read the results
Status and coverage explain what was verified.
Valid
The inspected check passed.
Error
A confirmed problem needs fixing.
Warning
Review the declaration or incomplete coverage.
Unavailable
The check could not establish a result.
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Canonical Tag Checker — FAQ
Understand the checks and their limits.
What are the limits?
One source and at most one different target, five redirects per document and 50 declarations per document. The check takes at most 20 seconds, with eight seconds and 2 MiB per document. Partial coverage is explicitly labeled.
What does this canonical checker inspect?
It reads canonical links in the source HTML and HTTP Link headers. If there is one valid target, it checks that destination’s response, canonical and noindex directives. It does not crawl the whole website.
Is a missing canonical always an error?
No. A missing declaration is a warning. A canonical pointing to another page or domain is not an error by itself; review whether it matches your intended preferred URL.
Does a valid canonical guarantee indexing?
No. The report shows declared signals. It does not identify Google’s selected canonical, compare page content or confirm indexing. JavaScript, robots.txt and sitemaps are outside the check.