Check canonical tags and detect potential duplicate content issues.
What is Canonical URL Checker?
Canonical URL Checker verifies the rel=canonical tag on any page to detect duplicate content issues. A canonical tag tells search engines which version of a page is the "original" when similar content exists at multiple URLs.
How to use this tool
Enter the URL to check.
The tool fetches the page and reads the canonical tag.
Review whether the canonical points to itself (correct) or another URL.
Check for common issues: missing canonical, pointing to wrong URL, or HTTP vs HTTPS mismatch.
Compare the canonical URL with what you expect to be indexed.
Frequently asked questions
What is a canonical URL?
It tells search engines which URL is the "official" version when the same content is accessible at multiple URLs. For example, example.com/page, example.com/page?ref=1, and example.com/Page should all canonical to one URL.
Should every page have a canonical tag?
Yes. Even if a page has no duplicates, a self-referencing canonical is best practice. It prevents issues when URL parameters are added by analytics tools or marketing campaigns.
What happens without a canonical tag?
Search engines guess which URL is the original, which can split ranking signals between duplicates. You might see the wrong URL ranking, or neither ranking well.
Can I canonical across domains?
Yes. Cross-domain canonicals tell Google the content originally lives on another domain. Use this for syndicated content or when the same article appears on multiple sites.