Free Tool
Canonical Tag Checker
Checks for canonical tag presence, self-referencing vs cross-domain canonicals, and duplicate canonical issues that can cause indexation problems.
Note: Some checks require fetching external URLs, which may be blocked by CORS restrictions in the browser. For URLs that can't be fetched directly, try pasting the HTML source instead. Full functionality can be connected via a server-side API proxy.
Why this matters
Canonical tags tell search engines which version of a page to index. Incorrect canonicals can cause duplicate content issues, split link equity, or make important pages disappear from search results entirely. This is one of the most commonly misconfigured SEO elements.
FAQ
A canonical tag (rel="canonical") tells search engines which URL is the master version of a page. It prevents duplicate content issues by consolidating ranking signals to one URL.
Yes, for the canonical version of a page. If a page is the master version, its canonical tag should point to itself. Only use cross-domain or cross-page canonicals when intentionally consolidating duplicates.
Conflicting canonicals (e.g., in HTML header and HTTP header) can confuse search engines. Google will typically ignore one, but the behavior is unpredictable. Always have a single, consistent canonical signal.
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