Enter any page URL. MrKeyword fetches it live, reads the rel=canonical tag and the HTTP Link header, then follows the canonical target to check that it answers HTTP 200, can be indexed and points to itself.
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Built on first-party data from Google and Bing
A canonical tag is a <link rel="canonical" href="…"> element in the page head that names the preferred URL when several addresses show the same or very similar content, such as tracking parameters, sorted product lists or http and https copies. Files that have no HTML head, like PDFs, can send the same signal in an HTTP Link header.
Google treats the canonical as a strong hint, not a rule. It weighs it with redirects, internal links, the sitemap and HTTPS, and it can pick a different URL when the signals disagree. Two canonicals that name different URLs, or a canonical that points at a redirect, an error or a noindex page, make it more likely that Google ignores your choice.
This checker reads both sources on the live page, then requests the canonical target without following redirects, so it can show the target's own status, noindex directives and canonical, and follow up to five pages to find chains and loops. For the full set of indexing signals on one URL, use the indexability checker.
Every rel=canonical in the page head and in the HTTP Link header, resolved to a full URL, with conflicts, relative URLs, http targets and query strings flagged.
Each canonical target is fetched live with its HTTP status, noindex directives and its own canonical, up to five pages deep.
The fictional northwind-plumbing.example adds ?ref=footer to a footer link, and the page's canonical names the clean address without the trailing slash. The site later moved every page to a trailing slash with a 301. This is what the checker shows for https://northwind-plumbing.example/boiler-repair?ref=footer:
| Canonical URL | Source |
|---|---|
| https://northwind-plumbing.example/boiler-repair | HTML |
| URL | HTTP status | Indexable | Its canonical |
|---|---|---|---|
| https://northwind-plumbing.example/boiler-repair?ref=footer | 200 | Yes | https://northwind-plumbing.example/boiler-repair |
| https://northwind-plumbing.example/boiler-repair→ https://northwind-plumbing.example/boiler-repair/ | 301 | No (HTTP 301) | None |
Example result for a fictional website (northwind-plumbing.example). It is produced by the checker's own code from the setup described above; run the checker for your own pages.
Pointing the tracked URL at the clean one is right, but the clean URL now answers 301, so Google has to resolve a redirect before it can use the hint and may choose another URL instead. The fix is to update the canonical tag in the page template to the final address, https://northwind-plumbing.example/boiler-repair/, so every page names a URL that answers HTTP 200 and points to itself. Read canonical tags explained for when to use a self canonical, and check the rest of the indexing signals with the indexability checker.
Usually left over from a migration or a trailing-slash change. Update the canonical to the final URL that answers HTTP 200.
Google will not use a missing or noindex page as the main version. Point the canonical at a live, indexable page, or use a self canonical.
A CDN or plugin often adds a Link header that the template does not know about. Remove one source or make both name the same URL.
Page A names B, and B names C (or A again). Point every duplicate straight at the one final URL.
Use an absolute https:// URL, so the canonical cannot resolve to the wrong host or protocol.
Check a page's canonical whenever URLs change or Search Console reports that Google chose a different canonical.
A canonical tag on a page that names that same page's URL. It tells Google which version of the address you prefer, for example without tracking parameters, so links and signals are counted for one URL.
No. Google treats rel=canonical as a hint. It can choose another URL when redirects, internal links, the sitemap or the content point elsewhere. Search Console URL Inspection shows the canonical Google selected.
It works badly. Google has to resolve the redirect and may pick a different URL. Point the canonical straight at the final URL that answers HTTP 200.
When a page sends two different canonical URLs, Google may ignore both. Keep one source, or make both name the same URL.
Yes. Google supports relative URLs but recommends absolute ones, such as https://example.com/page, because a relative path can resolve to the wrong host or protocol.