Check where your canonical tag points
Enter a URL. The checker reads the canonical from the HTML head and the HTTP Link header, compares it with the page, then fetches the canonical target to confirm Google can use it.
One page and its canonical target. To check a URL for other indexing blockers, use the index check.
- 12
- checks, from placement to target
- 3
- places read: head, body and Link header
- €0
- no signup
What the check tests
A canonical can be syntactically fine and still point Google to a redirect or a noindex page. The checker looks at both.
- 01
Where the canonical sits
The
<link rel="canonical">in the HTML head and the HTTPLinkheader. A canonical in the body is flagged, because Google only accepts it in the head. - 02
Exactly one
Different canonicals on one page, or an HTML tag and a Link header that disagree, are a conflict. The same URL set twice is flagged as a risk.
- 03
Absolute URL
Google supports relative canonicals but recommends absolute URLs with protocol and host.
- 04
Self or elsewhere
Whether the canonical names the page itself or another URL, compared with the final URL after redirects.
- 05
Variants of the same URL
http instead of https, www versus no www, trailing slash, upper and lower case, and query parameters.
- 06
The target, fetched
The canonical URL is requested: a redirect or an error status is a fail, so is a noindex in meta robots or X-Robots-Tag. Its own canonical should point to itself, not on to a third URL.
- 07
Mixed signals
noindex on the checked page combined with a canonical, and an og:url that names a different URL.
Questions
Does Google always follow my canonical?
No. Google describes rel="canonical" as a strong signal, like a redirect, and a sitemap as a weak one. If the signals contradict each other, Google may choose a different canonical than the one you set. The URL Inspection tool in Search Console shows which URL Google selected.
Does every page need a self-referencing canonical?
It is not required. Without one, Google picks the canonical itself. A self-referencing canonical states your preference explicitly, which helps when the same page is reachable with tracking parameters or other URL variants.
Can I use noindex instead of a canonical for duplicates?
Google advises against it for choosing a canonical within one site: noindex removes the page from Search completely, while rel="canonical" points signals to the preferred URL. Google also says not to use robots.txt for canonicalization.
Can I set the canonical in the HTTP header?
Yes. Google supports rel="canonical" in the HTTP Link header, and it is the way to set a canonical for PDFs and other non-HTML files. Use an absolute URL there, and don’t combine it with a different canonical in the HTML.
The canonical is correct, but the page is still not indexed.
Then the cause is elsewhere. The index check looks for page-level blockers such as noindex, robots.txt rules and error status codes.
Canonicals fine, but Google indexes the wrong URLs?
The Search & AI Diagnostic (€290) checks indexing, technical setup and AI visibility for your site and tells you what to fix first.