Check a page
Canonical tag checker
Check a page's canonical tag and HTTP header in one go: missing, doubled, relative, or pointing at a page that redirects, breaks or is kept out of search.
Free · No signup · Reads public pages only
How it works
Paste the address of the page you want to check.
We read its HTML and headers. If the canonical points to another page, we fetch that page too.
You get every canonical we found, where it leads, and what to fix.
What a canonical tag does
When the same content lives at more than one address (with and without www, with tracking parameters, a print version, a product listed in two categories), search engines pick one address to show in results. The canonical tag is how you say which one you prefer. It's one line in the page's head, <link rel="canonical" href="https://example.com/page">, or an HTTP header, which is how PDFs and other files that aren't web pages declare one.
Google's documentation calls it a strong hint, not a command. Google weighs it alongside redirects, internal links, the addresses in your sitemap and whether the page uses HTTPS. When those signals agree, Google usually follows your canonical. When they disagree, it may choose a different address.
How to read the result
A page that names itself as the canonical (a self-referencing canonical) is the normal, healthy case. It tells search engines this address is the one to keep, even when someone links to it with extra parameters on the end.
A canonical that points to another page is a statement: this page is a copy, rank the other one. That's right for duplicates and filtered views, and a mistake on a page you want in search results. When we find one, we check the target as well. It should load with a 200 status, without redirecting, without a noindex, and name itself as its own canonical.
- No canonical at all. Not an error, but you leave the choice to Google.
- More than one canonical, or the HTML and the header disagreeing. Google's guidance is that conflicting canonicals may all be ignored.
- A relative address such as /page. Google recommends full URLs.
- A different protocol or host: http instead of https, www instead of no www, or another domain.
- A target that redirects, returns an error, is set to noindex, or points somewhere else again.
- An og:url that names a different address, or hreflang tags that leave out the page itself.
Common canonical mistakes
The template mistake: every page on the site points its canonical at the homepage, usually because a theme or plugin hard-coded it. Search engines read that as "all these pages are copies of the homepage". Paginated lists that point pages 2, 3 and 4 at page 1 are a smaller version of the same problem: the items on the later pages get harder to find.
Mixed signals are the other common one. The canonical says https://example.com/page, but internal links, the sitemap and redirects all use https://www.example.com/page/. Pick one form of each address, trailing slash included, and use it everywhere. And don't put a canonical to another page and a noindex on the same page. One says "index that one instead", the other says "drop this", and Google's documentation advises against using noindex to choose a canonical.
What this checker can't see
It reads what your server sends before JavaScript runs. If a script adds or changes the canonical later, Google may see the changed version, but many other crawlers won't. Keep the canonical in the HTML your server sends.
It also can't tell you which address Google actually chose. For that, open Search Console, inspect the page with URL Inspection and compare the user-declared canonical with the Google-selected canonical. If they differ, other signals (links, redirects, the sitemap) are pulling Google somewhere else.
Questions people ask
Does every page need a canonical tag?
It isn't required, but a self-referencing canonical on every page you want in search is cheap insurance. It stops tracking parameters, session IDs and capitalization differences from creating copies that compete with the real address.
Is a canonical the same as a redirect?
No. A redirect sends people and crawlers to the other page. A canonical leaves the page where it is and only asks search engines to credit the other address. Use a redirect when the old page shouldn't exist anymore, and a canonical when both versions need to stay reachable.
Can a canonical point to another website?
Yes. A canonical to another domain is allowed, for example when an article is republished on a partner's site. Make sure it's intended: a stray one asks search engines to rank that site instead of yours.
How do canonicals work with hreflang?
Each language version should name itself as its canonical, not the main language version, and its hreflang tags should list every version including itself. Pointing every language at one canonical tells Google the translations are duplicates.
Why did Google pick a different canonical than mine?
Usually because other signals disagree: internal links or the sitemap use another address, the page redirects, or the two pages aren't really duplicates. Search Console's URL Inspection shows the address Google chose.
Is this canonical checker free?
Yes. No signup, no limit you'll hit in normal use. It only reads public pages.
Want it done for you?
Romeo keeps canonicals consistent across your site
He checks every page's canonical against your redirects, sitemap and internal links, fixes the ones pointing at the wrong address, and sends you the changes to approve before anything goes live.
