Canonical Tag Checker
Verify your rel="canonical" tag points to the right URL. A wrong or missing canonical tells Google to index the wrong page — or splits ranking signals across duplicates.
§ what this tool checks
Rules applied to every scan.
The canonical tag is how you tell search engines which URL is the "real" one when the same content lives at multiple addresses. Get it wrong — point it at the wrong page, another domain, or a relative path — and you can deindex pages you wanted ranked or split ranking signals across duplicates. This tool reads your canonical tag, resolves it to an absolute URL, and confirms whether it correctly references the page itself.
Presence of a rel="canonical" link tag
Canonical resolved to an absolute URL
Whether the canonical is self-referencing
Canonical pointing to a different page or domain
Canonical also declared in the HTTP Link header
Relative or malformed canonical values
§ faq
Questions, answered.
What is a canonical tag?
A canonical tag (<link rel="canonical" href="...">) tells search engines which URL is the preferred, "master" version of a page when the same or very similar content is reachable at multiple URLs. It consolidates duplicate-content signals onto one URL so ranking authority is not split across query-string variants, tracking parameters, or www/non-www duplicates.
What is a self-referencing canonical and do I need one?
A self-referencing canonical is a canonical tag that points to the page it sits on — the normal, recommended setup for any page that should be indexed on its own. It removes ambiguity for crawlers and protects against duplicate URLs created by tracking parameters. Unless a page is intentionally a duplicate of another, its canonical should point to itself.
What happens if my canonical points to the wrong page?
A wrong canonical tells Google to index a different URL instead of the current page — so the current page can effectively disappear from search while ranking signals flow to a page you did not intend. Pointing every page at the homepage, or leaving a templated canonical that points to a staging or example URL, are common and costly mistakes that can deindex large parts of a site.
Should canonical URLs be absolute or relative?
Always absolute — include the full protocol and domain (https://example.com/page), not a relative path like /page. Google can interpret relative canonicals, but they are ambiguous and easy to resolve incorrectly, especially across HTTP/HTTPS or www/non-www. An absolute canonical leaves no room for misinterpretation.
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