HTML and HTTP header canonical
Reads both the HTML link rel canonical tag and the HTTP Link response header. Most checkers only read one source. This finds conflicts between the two that hide bugs from naive tools.
Canonical URL Checker
Paste any URL to instantly find the canonical URL of a webpage. The tool reads both the HTML link rel canonical tag and the HTTP Link header, then tells you if the page is self-referencing, missing a canonical, or pointing to another URL.
Guide
How to Check the Canonical URL of Any Page
1
Enter the URL
Paste any webpage URL into the input field.
2
Click Check Canonical
Click Check and the tool reads the canonical tag from headers and HTML.
3
Review Your Results
See whether the page is self-referencing or pointing to another URL.
How the Canonical URL Checker validates canonical tags and prevents duplicate content
A canonical URL checker is a free SEO tool that reads the canonical tag from a webpage (both the HTML link rel canonical element and the HTTP Link response header) and reports whether the page is self-referencing, missing, points to a different URL, or has conflicting signals between the two sources.
This tool runs the same checks Googlebot does when it decides which version of a page to index: self-referencing detection, HTTP vs HTML conflict detection, HTTPS and trailing-slash consistency, www vs non-www match, cross-domain canonical flags, and detection of multiple canonical tags on the same page. Use it after every theme change, plugin update, or site migration to catch broken canonicals before they drop your rankings.
Benefits
What this Canonical URL Checker catches
Self-referencing detection
Confirms whether the canonical URL on a page points back to itself (the safe default) or to a different URL. Pages that canonical to another URL often have intentional or accidental ranking transfer.
Cross-domain and HTTPS mismatch
Flags canonicals that point to a different domain, an HTTP version when the page is HTTPS, or vice versa. Both signals tell Google to consolidate rankings somewhere else.
Trailing slash and www consistency
Detects when the canonical disagrees with the page URL on trailing slash, www prefix, or query parameters. These tiny mismatches cause real duplicate-content issues.
Multiple canonical tag detection
Some pages have two or more canonical tags from theme bugs, plugin conflicts, or migration errors. Google ignores all of them when this happens. The tool flags the count.
Googlebot user-agent fetch
Pulls the page using a Googlebot-style user agent so cloaked or geo-redirected pages return the same canonical Googlebot sees, not a localized variant.
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FAQ
Frequently Asked Questions
Common questions about canonical URLs and how to use this checker.
What is a canonical URL and why does it matter for SEO?
A canonical URL is the preferred version of a webpage that you tell search engines to index when several URLs serve similar or duplicate content. Without a canonical tag, Google picks one version on its own, and that pick may not be the one you want ranking. A canonical URL checker confirms the canonical tag is in place and points to the right URL.
How do I find the canonical URL of a webpage?
Paste the page URL into this Canonical URL Checker. The tool fetches the page server-side, reads the link rel canonical tag in the HTML head, also reads the Link HTTP response header, and shows you the canonical URL from both sources along with whether the page is self-referencing.
What is the difference between HTTP header canonical and HTML tag canonical?
The HTML canonical tag lives inside the page source as a link rel canonical element. The HTTP header canonical is set by the server in the Link response header before the browser parses the HTML. Both signals are valid for Google. If they conflict, Google may ignore both. This tool reads both and flags any mismatch.
What is a self-referencing canonical URL?
A self-referencing canonical is when a page declares itself as its own canonical, for example /pricing has a canonical tag pointing back to /pricing. Self-referencing is the safe default for most pages and tells search engines this URL is the master version. The checker flags whether your page is self-referencing or pointing elsewhere.
Can a page have two canonical tags?
Technically yes, plugins, themes, or migration scripts can output multiple canonical tags on one page. Google does not pick the strongest one, it ignores all of them when it sees a conflict. The Canonical URL Checker counts the canonical tags and flags any page with more than one so you can fix the source.
How do I fix a missing canonical tag?
Add a link rel canonical element inside the head of the HTML, pointing to the URL you want as the master version. In WordPress, Yoast and Rank Math both add canonical tags automatically. For static sites, add the tag in the head template. Re-run the Canonical URL Checker after to confirm.
What does a cross-domain canonical mean?
A cross-domain canonical points from a page on one domain to a page on another domain. This is rare and intentional, for example syndicated content telling Google to credit the original site. If you see a cross-domain canonical on your own site and it was not intentional, fix it immediately, you are giving away ranking credit.
Is this Canonical URL Checker free?
Yes, the tool is 100 percent free with no daily cap, no signup, no app to install. Check as many URLs as you need. The tool runs on our server and is also used internally by the Pixellize SEO team for audits.