Canonical tag checker
Enter a page address to find its canonical tag, check the address it points to really works, and see whether anything on the page tells Google not to index it.
- No cost
- No sign-up
- No email
- No Google sign-in
- No subscription
- No limits for normal use
What the canonical checker tests
The canonical tag
Whether the page has one, whether it points to itself or another page, and whether there are two different ones (Google then ignores both).
The target address
We load the canonical address to check it answers 200 directly, rather than redirecting, returning an error or being blocked.
Noindex signals
Meta robots, googlebot tags and the X-Robots-Tag header, so you can see in one place whether Google is allowed to index the page.
What is a canonical tag?
A canonical tag is a line in a page's head, <link rel="canonical" href="…">, that tells search engines which address is the main version of the page. The same page can often be reached several ways: with and without www, with tracking codes such as ?utm_source=, or through different category paths in a shop. The canonical tag gathers all of them into one address, so links and ranking signals aren't split, and Google shows the address you want in its results.
Common canonical mistakes
- Every page pointing at the home page. A theme setting or a plugin mistake that tells Google to drop all your inner pages.
- Canonical to a redirect or a 404. Google then has to guess, and often picks a different address from the one you wanted.
- http or the wrong domain. A canonical to http:// on an https site, or to a staging or old domain, left over from building the site.
- Noindex plus a canonical to another page. Mixed signals: one says "drop this page", the other says "this is a copy".
- A canonical in the body. Google only reads canonical tags in the <head>.
How to fix the problems it finds
On WordPress, Yoast SEO and Rank Math set a self-referencing canonical on every page; you can change one page's canonical in its SEO settings. Shopify adds canonicals itself. If the checker finds a noindex you didn't expect, look for "Discourage search engines" in WordPress Settings → Reading, or the page's own SEO settings. Check the redirects with our redirect checker, then ask Google to re-crawl the page from Search Console.
What it can't check
A canonical tag is a strong hint, not an order: Google can still choose a different main address, and only Search Console's URL Inspection shows which one it picked. We don't run JavaScript, so a canonical changed by a script after the page loads isn't seen here. robots.txt rules are checked by our robots.txt tester.
Frequently asked questions
Is the canonical checker free?
Yes. No sign-up, no email and no subscription, with only a fair-use limit to stop bots.
Should every page have a canonical tag?
It's good practice. A canonical pointing to the page's own clean address protects it against copies created by tracking codes, filters and www or http versions.
Does a canonical tag pass link value?
Google treats it as a strong hint to combine the duplicate addresses, including their links, into the chosen main version.
What's the difference between a canonical and a 301 redirect?
A 301 sends visitors and Google to the new address. A canonical leaves both addresses working for visitors and only tells search engines which one to show.
Related guides
Duplicate content
Duplicate content in plain English: is there a Google penalty, what causes it on small sites and shops, and how to fix it with canonicals and redirects.
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