Canonical Tag Checker
Check the canonical URL a public page declares and verify the surrounding signals: HTML head vs body placement, HTTP Link canonicals, redirects, target status, noindex conflicts and canonical chains.
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Fetching the source page and canonical target…
Canonical report
Canonical analysis
Declared signals
Canonical annotations
Every canonical found in the HTML or HTTP response.
Diagnostics
Canonical findings
No artificial SEO score—each finding is tied to a concrete signal.
Source & target
URL evidence
Source response, canonical target and indexing directives.
Redirect chains
Methodology and limitations
Canonical SEO
What a canonical tag checker should verify
A canonical is a preference signal. The URL itself, placement, target health and surrounding indexing signals all matter.
A rel="canonical" annotation tells search engines which URL you prefer as the representative of duplicate or substantially similar content. Google describes canonical link annotations as a strong canonicalization signal, while redirects and sitemap inclusion can reinforce the same preference. Google can still select a different canonical when other signals disagree.
Canonical in the HTML head
For HTML pages, Google accepts the canonical link element in the document <head>. A canonical link found in the body is reported for review.
HTTP Link canonical
Canonicalization can also be declared in an HTTP Link response header, including for non-HTML files. Mixing HTML and HTTP methods increases the chance of conflicting values.
Absolute target URL
Relative canonicals are supported, but Google recommends absolute URLs because they are less likely to be accidentally resolved against a staging or unintended host.
Target returns a usable page
A canonical that points at a redirect, error page or inaccessible endpoint adds ambiguity. This checker follows the declared target and reports the response chain.
Noindex conflicts
If the intended canonical target is marked noindex, the signals conflict. Google also advises against using noindex as a substitute for canonicalization within a site.
Canonical chains
If Page A canonicals to B and B canonicals to C, point A directly at the final preferred representative rather than maintaining an unnecessary canonical chain.
Self-referencing vs cross-referencing canonicals
A self-referencing canonical points back to the same preferred page and is commonly used to make the intended URL explicit. A cross-referencing canonical points to another URL and can be appropriate when the current page is a duplicate, parameter variation or another equivalent version. Cross-domain canonicalization is also possible, but it should be intentional and supported by genuinely similar content.
Canonical tags are hints, not guaranteed Google-selected canonicals
This tool can verify what your server declares; it cannot know which URL Google ultimately selected as canonical. Google Search Console's URL Inspection data is the appropriate source when you need the Google-selected canonical for a specific property.
Canonical tag vs redirect vs noindex
Use a permanent redirect when an old or duplicate URL should send users and crawlers to a replacement. Use canonicalization when multiple URLs need to remain accessible but represent the same or highly similar content. Use noindex when a page should not appear in search at all. These mechanisms solve different problems and should not be stacked without understanding their effects.