Canonical Checker
Check canonical URLs
Frequently Asked Questions
What is a canonical tag and why does it matter for SEO?
A canonical tag (<link rel="canonical" href="...">) tells search engines which URL is the preferred version of a page. It prevents duplicate content issues when the same content is accessible via multiple URLs (www vs non-www, HTTP vs HTTPS, URL parameters).
How do I check if my canonical tags are correct?
Enter your URL. The tool checks: is a canonical tag present, does it point to the correct URL, is it self-referencing or cross-domain, does it match the actual URL, and are there conflicting signals (canonical vs redirect vs sitemap). Issues are flagged with explanations.
What are common canonical tag mistakes?
Pointing to a non-existent URL. Canonical to a redirected URL. Multiple conflicting canonical tags. Canonical pointing to a different page (not a duplicate). Using relative URLs instead of absolute. Missing canonical on paginated content. The checker identifies all these issues.
Should every page have a canonical tag?
Yes. Every indexable page should have a self-referencing canonical tag. This is a best practice even when there are no duplicates. It prevents issues from URL parameters, session IDs, or tracking codes creating unintended duplicate URLs.
How does canonical tag interact with 301 redirects?
301 redirects force browsers to the new URL. Canonical tags are hints (search engines may ignore them). Use 301 redirects when the URL has permanently changed. Use canonical when both URLs should remain accessible but one is preferred for indexing.