Check canonical URL

AI SEO tools

Enter a URL to see which canonical search engines would honor, whether it is self-referencing, and conflicts like multiple canonicals, relative URLs, or a noindex combination. The URL you enter is fetched by our server to read its HTML and headers.

Guide

What is the Check canonical URL tool?

Check canonical URL is a free tool that reads every canonical signal on a page and shows which canonical URL search engines would honor. Enter a URL and it fetches the page, follows redirects, then inspects both the rel=canonical link tag in the HTML and the rel=canonical entry in the HTTP Link header.

A page can declare its canonical in two places, and this tool reads both:

SignalWhere it livesBest forNotes
rel=canonical link tagHTML <head>Regular HTML pagesThe most common form; ignored when it sits outside <head>
rel=canonical Link headerHTTP response headerPDFs and other non-HTML filesAlso valid for HTML; must agree with the link tag
No canonicalNowhereNot recommendedSearch engines pick a version themselves

When it comes in handy

  • You migrated or redesigned a site and want to confirm every template still emits the right canonical.
  • A page ranks with the wrong URL variant (with parameters, without a trailing slash, http instead of https) and you suspect canonical problems.
  • Your CMS or SEO plugin injects its own canonical and you want to check it does not conflict with one already in the template.
  • You syndicate content and need to verify the copy points its canonical at the original article.
  • Google Search Console reports "Duplicate, Google chose different canonical than user" and you want to see what the page actually declares.

How to use

  1. Paste the URL of the page you want to inspect.
  2. Press Check. The tool fetches the page on our server, follows redirects, and reads the HTML and headers.
  3. Review the results: the effective canonical URL, whether it is self-referencing, every declaration found with its source, and a list of flagged problems.

For example, checking https://example.com/blog/post?utm_source=x where the page declares <link rel="canonical" href="https://example.com/blog/post"> reports the canonical as https://example.com/blog/post and marks it as canonicalizing to another URL, which is exactly what you want for a parameterized duplicate.

Which canonical problems does it flag?

CheckSeverityWhat it means
Missing canonicalWarningNo declaration anywhere; search engines choose a version themselves
Conflicting canonicalsErrorDeclarations point to different URLs; Google usually ignores all of them
Duplicate declarationsWarningThe same canonical is declared more than once
Invalid URLErrorA canonical value cannot be parsed as a URL
Relative URLWarningValid but error-prone; Google recommends absolute URLs
#fragment in the URLWarningFragments are invalid in canonicals and get dropped
Canonical outside <head>WarningSearch engines ignore canonical tags in the body
http target on an https pageWarningThe canonical downgrades to the non-secure version
Cross-domain canonicalInfoValid for syndicated content; confirm it is intentional
noindex + canonical to another URLWarningMixed signals; the noindex can keep the canonical from consolidating

Notes

  • The tool reports what the page declares. Google treats canonicals as a hint, so the URL it ultimately picks can still differ; compare with the URL inspection report in Search Console.
  • Redirects are followed first, and the canonical is read from the final URL. To audit the redirect chain itself, use the redirect checker.
  • To check whether a page can be indexed at all, use the noindex checker. To inspect the page's OGP and social sharing tags, use the OGP checker.

Operated by

unbounded pioneering inc
Timothe AI

Tools by Timothe AI is a suite of free tools built and operated by unbounded pioneering inc, the company behind Timothe AI.

Ryosuke Suzuki
Ryosuke SuzukiFounder & CEO

Founder & CEO of Unbounded Pioneering Inc., the company behind Timothe AI, and an expert in machine learning and AI product development. He began his career in machine learning research at a university laboratory, then designed and built large-scale products as a software engineer at PLAID, Rakuten, and Recruit, while also driving new business development. Now specializing in generative AI and AI products, he works across both engineering and business development, and is a named inventor on multiple granted patents in web technology.

Named inventor on granted patents JP6887648 & JP7480958 · Patent pending on Timothe AI technology

Get in touch

Thanks for reaching out

Thank you for your interest in our company. A member of our team will get back to you within one business day.

What we can help with

  • Adopting and getting the most out of Timothe AI
  • A demo or trial of Timothe AI
  • AI adoption in general (beyond our own product, too)
  • Alliances and partnerships
  • Any other questions

Talk to us online

You can also book a meeting directly from the calendar.

Pick a template or write your own message.