Is this page telling Google to index it?
Enter a page. We read its canonical tag and then follow it — because a canonical pointing at a page that does not exist looks perfectly correct in the markup.
We do not store the pages people check.
Anyone whose page will not index.
The canonical tag is four words of markup that can remove a page from search entirely, and it fails without any error. The page loads, the tag is present, the markup validates. And the page is quietly asking engines to credit a different url.
It is also the first thing worth ruling out when a page is not indexed, because it takes ten seconds and the alternative explanations take weeks.
Six things, and the first one needs a second request.
Where the canonical actually goes
We follow it. A canonical pointing at a page that returns 404 hands an engine a dead address while the markup looks perfect, and the page can end up indexed as neither. Reading the tag is not the same as checking it.
More than one canonical
An engine ignores them all. Two canonical tags leave a page worse off than no canonical at all, and plugins add a second one routinely.
A canonical outside the head
Ignored entirely, while looking completely present in your markup. This is the one people stare straight past.
Pointing at another page
Correct when deliberate. When the tag was copied with a template, every page using it is telling engines not to index itself. And the markup is identical either way, so we say which it looks like rather than calling it wrong.
Contradictions in the same head
noindex alongside a self-canonical is two opposite instructions, and noindex wins. An og:url that disagrees means shares and crawls resolve to different pages.
Http, relative and malformed values
An http canonical on an https page names a different url. A relative one breaks the moment the content moves. A malformed scheme does not fail, it silently resolves as a path on your own site.
We got that email too.
Google sent us that message on 7 October 2026. It means you declared one url as the canonical version of a page, and Google decided a different url represents that content better.
Your tag is a signal, not an instruction. Google weighs it against your internal links, your redirects, your sitemap, and which version of the page it encounters most often. When all of those point one way and your tag points another, the tag loses. And it is usually right to.
So the first useful step is not to argue with the engine. It is to confirm what your page actually declares, because a surprising share of the time the tag does not say what its owner believes it says. That is the half you control, and this tool checks it.
The honest limits.
Which page an engine actually picked
Only Search Console tells you that, for sites you own. This tool tells you what you declared — which is the half you control, and the half worth getting right first.
Whether a cross-canonical is wrong
A deliberate cross-canonical and a template left on the wrong page produce identical markup. We report what the tag does and let you say which it is.
Canonicals set by HTTP header
A Link: rel=canonical response header is legal and rare. We read the markup, so a header-only canonical will not appear here.
Tags injected by JavaScript
If the canonical is added after load, we will not see it. And neither will some crawlers, which is worth knowing in itself.
Five moments worth the ten seconds.
When Search Console says Google chose a different canonical
The message that sends most people looking for a tool like this. Start by checking what your page actually declares.
After adding or updating an SEO plugin
A second canonical tag is the classic outcome, and it voids the one you meant.
After a migration or a domain change
Absolute canonicals carrying the old domain parse perfectly and point at nothing.
When a page will not index
Before assuming it is a content problem, check whether the page is telling engines to credit a different url.
On a template used by many pages
One wrong canonical in a template is one wrong canonical on every page that uses it.
Most of them read the tag and stop.
Reading the tag is the easy half. It tells you a canonical exists and what it says. It does not tell you whether the address it names is a real page.
This one requests that address. A canonical pointing at a 404, or at a url that redirects somewhere else again, is a page handing an engine an address that goes nowhere. And nothing about the markup looks wrong. It costs a second request, which is why most free tools skip it.
It also checks the rest of the head for contradictions. A page can declare a perfect canonical and a noindex in the same breath, and the canonical is not the one that wins.
Indexed is the floor. Being named is the job.
A correct canonical means your page is eligible to be found. It says nothing about whether an assistant names your business when a customer asks who to hire. That depends on the page answering a real question, and on the facts about your business agreeing across every source an engine can reach.
We publish how we test that, including the answers where we are not named, on our methodology page. Prices are on the pricing page.
What owners ask about this.
Google says it chose a different canonical than I did. What does that mean?
You declared one url as the canonical version and Google decided another url is the better representative of that content. It is a signal, not a command, Google weighs your tag alongside internal links, redirects, sitemaps and which version it sees more often. The first thing to confirm is that your tag says what you think it says, which is what this tool checks.
Is it bad to have no canonical at all?
Not by itself. Engines pick one anyway and usually pick the obvious one. The cost is that you have no say and no visibility. You find out what they picked only when it is wrong. A self-referencing canonical on every page is cheap insurance.
Why would two canonical tags be worse than none?
Because an engine faced with two contradictory declarations discards both rather than guessing. A page with one correct tag is fine, a page with none is adequate, and a page with two has thrown away its own answer. This happens most often when a theme and a plugin each add one.
My canonical points at another page on purpose. Is that wrong?
No. That is exactly what cross-canonicals are for, a printer-friendly version, a syndicated copy, a parameterised url. The problem is that a deliberate cross-canonical and a template left on the wrong page look identical in the markup, so we report what the tag does rather than calling it a mistake.
Does the canonical have to be the full url?
A relative canonical does resolve. But it resolves against wherever the page is being served, so the same template on a different path points somewhere else. And the failure is silent. Every guide recommends the absolute url for that reason.
Does a canonical do the same job as a redirect?
No. A redirect sends people and crawlers elsewhere; a canonical leaves the page where it is and asks engines to credit another url. If you want one page gone, redirect it. If you want two live pages and one of them credited, that is the canonical.
Do canonicals affect AI search?
Indirectly, which is the honest answer. Assistants that answer from a search index inherit whatever that index consolidated, so a page that was excluded by its own canonical is not available to be cited. It does not change how an assistant reads a page it has already found.
Do you store the pages people check?
No. The check runs, the result goes to your browser, and nothing is kept. There is no sign-up and no email field on this page.
Related: Robots.txt checker · Sitemap validator · Structured data validator · How we test AI answers
By Steven Allbright, founder, Ultimate Elite Solutions · Last updated: 2026-10-08
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