Canonical URL Checker
Check the canonical tag of any page, or up to 25 at once. See where each canonical is declared, whether it points to the page itself or somewhere else, and whether the target returns 200, redirects, is noindex or points back, which Google treats as a conflict.
- Reads head, body and HTTP header
- Checks the canonical target too
- Finds chains, loops and conflicts
Also check how the page is shared and linked: Redirect Checker, Hreflang Checker and On-Page SEO Checker.
Every way a canonical tag can go wrong
A canonical tag is a hint to search engines about the preferred URL for a page. These checks find the mistakes that make Google ignore it.
Where it is declared
In the head, where it works, in the body, where it is ignored, or in the HTTP Link header. Conflicts between them are flagged.
More than one
Two canonical tags that disagree are ignored by Google. Plugins and themes often each add one.
Self or another page
A canonical that matches the page is self-referencing. One that points elsewhere tells search engines the page is a duplicate.
Near matches
http versus https, www versus non-www, and trailing slash differences that quietly split signals.
The canonical target
The URL it points to is fetched: it should return 200, not redirect, not be noindex and be canonical itself.
Chains and loops
Page A canonicalizes to B and B to C, or A and B point at each other. Search engines ignore both.
Canonical problems, why they matter and how to fix them
Most canonical errors fall into a few groups.
| Problem | Why it matters | How to fix it |
|---|---|---|
| No canonical tag | Search engines choose the preferred URL themselves, which can split signals across duplicates. | Add a self-referencing canonical to every indexable page. |
| Multiple canonical tags | Conflicting tags are ignored. | Keep one tag. Check plugins, themes and templates. |
| Canonical in the body | Only the head is read, so the tag has no effect. | Move it into the head. |
| Relative or http canonical | Easy to get wrong, and an http canonical on an https page points at the wrong version. | Use the full https:// URL of the preferred page. |
| Canonical to a redirect or 404 | The preferred URL is not a live page, so the hint is ignored. | Point it at the final 200 URL. |
| Canonical chain or loop | Search engines follow one canonical only. A chain or loop is ignored. | Point every page straight at the final canonical page. |
| Noindex and canonical elsewhere | The signals conflict: drop the page, or consolidate it, not both. | Choose noindex or a canonical, not both. |
How to check a page's canonical tag
Four steps from a URL to a clear answer.
Enter the URLs
Paste up to 25 pages, or switch to Paste HTML for a page that isn't live yet.
Read the type
Self-canonical is the normal case. Points elsewhere means the page is treated as a duplicate.
Open the details
See where the tag is declared, the final URL and what the canonical target returns.
Fix and re-check
Correct the tag, redirect duplicate versions to the preferred URL, then check again.
How to use canonical tags well
A few habits keep canonicals reliable.
Self-reference every page
Each indexable page should declare itself as canonical. It protects against tracking parameters and scraped copies.
Use absolute https URLs
Include the protocol and the exact host, with the same trailing-slash style your site uses.
Keep signals consistent
Internal links, the XML sitemap, hreflang and og:url should all use the canonical URL.
Never canonicalize to a redirect or noindex page
The target must be a live, indexable page.
Don't point everything at the home page
Google treats that as a mismatch and may ignore it.
Remember it's a hint
Google may choose another URL if redirects, links and content point elsewhere. Make all signals agree.
What a canonical URL is and why Google may not follow your tag
When the same or very similar content can be reached at several addresses, search engines have to choose one to show. That chosen address is the canonical URL. You can suggest it with a rel="canonical" link element in the head, an HTTP Link header, redirects or your sitemap. Google's guide to consolidating duplicate URLs calls the canonical tag and redirects strong signals and the sitemap a weak one.
None of these is an order. Google may choose a different canonical for reasons such as content quality or technical signals, and Search Console reports it when Google picks another URL than the one you declared. The more your signals agree, the more likely your choice is used. A canonical that points to a redirect, a noindex page or a different page entirely is a conflict that Google can resolve in its own way.
A canonical checker reads the tag the way a crawler would. It shows where each canonical is declared, whether it names the page itself or another URL, and what the target returns. Page and target are tested together because the tag alone cannot tell you whether it will work. A tag can be valid HTML and still point at a URL that redirects, errors or asks not to be indexed.
When to check canonical tags
Check a sample from every template, and every page whose indexing status looks odd.
When Google picks a different canonical
Search Console says Google chose a different URL than the one you declared. Check what your tag really says and what the target returns.
After installing or switching a plugin
A theme and an SEO plugin can each print a canonical tag. Check one page of each type to confirm there is only one and that it matches.
After a migration
New pages sometimes keep canonicals that name the old domain, staging or a redirected URL. Test the key pages and confirm they point at their own new address.
On filtered and parameter URLs
Faceted navigation and tracking parameters create many addresses for one page. Check that they point at the clean URL you want indexed.
For JavaScript-built pages
Paste the HTML or fetch the page to check whether the canonical exists in the server response and not only after scripts run.
On multilingual sites
Each language version should point at itself, with hreflang annotations pointing between them. Check that the canonical and hreflang URLs match.
Canonical tag mistakes and how to fix them
Most canonical problems are conflicts between signals, so the fix is to make them agree.
Different canonicals from different methods
What goes wrong: A canonical in the HTML head, another in an HTTP header and a third implied by a redirect can disagree. Google says not to specify different canonicals for the same page.
The fix: Pick one method, usually the link element in the head, and remove the others. Check what plugins and the server add.
A canonical outside the head
What goes wrong: Google only accepts the link element if it appears in the head of the HTML. A tag injected into the body by a script or builder is not used.
The fix: Output it in the head in the server-generated HTML. If it is added with JavaScript, make sure scripts do not change a canonical that is already there.
Using noindex or robots.txt to pick a canonical
What goes wrong: Google advises against both. A page blocked in robots.txt can still be indexed without its content, and noindex would block the page from Search entirely instead of consolidating it.
The fix: Use rel="canonical" or a redirect to point to the preferred URL, and let crawlers reach both pages so they can read the signal.
Relative or fragment canonicals
What goes wrong: Relative paths work but Google does not recommend them, because small errors in a path can send the tag to the wrong address. Fragments are generally not supported.
The fix: Write the full absolute URL with https:// and the exact host. Never use a #fragment as a canonical.
Canonical to a redirected or error URL
What goes wrong: If the canonical target redirects, the redirect says one thing and the tag says another. If it returns an error, there is no live page to prefer.
The fix: Point the tag at the final URL that returns 200. Update internal links and the sitemap to the same address.
Everything canonicalised to one page
What goes wrong: Setting every page's canonical to the home page, or to a category, tells Google that unrelated pages are duplicates. Google may ignore the hint, and the pages can lose their own visibility.
The fix: Use self-referencing canonicals on distinct pages. Point a canonical elsewhere only when the page really is a duplicate or near copy.
Canonical terms explained
- Canonical URL
- The address of the version of a page that you want search engines to treat as the main one when several addresses show the same content.
rel="canonical"- A link element, or an HTTP
Linkheader for non-HTML files such as PDFs, that names the preferred URL for a page. - Self-referencing canonical
- A canonical tag on a page that names the page's own address. Google recommends including one on the canonical page itself.
- Duplicate content
- The same or very similar content reachable at more than one URL, such as http and https versions or parameter variants.
- Canonical signal
- Anything that points to a preferred URL: redirects, the canonical tag, the sitemap and internal links. Search engines weigh them together, so they should agree.
- Google-selected canonical
- The URL Google actually treats as canonical, which can differ from the user-declared one. URL Inspection in Search Console shows both.
- Cross-domain canonical
- A canonical that names a URL on another domain. It asks search engines to prefer the other site, so use it only when that is the intention.
- Canonical chain
- Page A names page B as canonical, and B names C. Point A directly at the final page so the signal is not left to interpretation.
Related tools, guides and services
Canonicals only work when the other signals agree. These check those signals.
Redirect Checker
Check that duplicate versions of a URL redirect to the preferred one in a single hop.
ToolHreflang Checker
Confirm that hreflang URLs are the canonical versions of each language page.
ToolMeta Tag Checker
Review the canonical alongside the title, description and robots tags.
GuidePages not indexed: causes and fixes
See how canonical status messages in Search Console map to causes and fixes.
GuideSEO audit errors that matter
Read why canonical conflicts rank among the audit issues worth fixing early.
ServiceTechnical SEO service
Get canonicals, redirects and indexing signals reviewed and corrected.
Built by
Madhav Kushwaha
SEO, AEO, GEO & Digital Marketing Consultant in Kathmandu, Nepal, and trainer at ODcrU Academy and TechAxis Institute. I built this checker because canonical problems are quiet. The page looks fine and ranks, until a plugin adds a second tag, a migration leaves canonicals pointing at redirected URLs, or two pages canonicalize to each other. Checking the tag and the page it points to together is what finds those.
Canonical URL Checker: Frequently Asked Questions
More free SEO tools
Canonicals, redirects, hreflang and internal links all tell search engines which URL is the right one. Check them together.