Free tool
Canonical Tag Checker
A canonical tag tells Google which URL is the real one. Point it at the wrong page — a mistake many CMS themes make by default — and Google drops your pages as duplicates. Check yours in seconds.
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What a canonical tag does
It consolidates duplicate versions of a page (www vs non-www, with and without tracking parameters) into a single URL, so ranking signals accumulate in one place instead of being split.
The mistake that erases sites
If every page canonicalises to your homepage, you are telling Google that only the homepage deserves indexing. It is one of the fastest ways to lose an entire site's rankings, and it is almost always accidental.
Self-referencing is the default
Unless you are deliberately consolidating duplicates, every page should canonicalise to itself using an absolute HTTPS URL. Our checker flags cross-domain and mismatched canonicals automatically.
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Run the full 35-point audit.
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