Canonical Tag Checker
Check a page’s canonical URL, whether it resolves, and if it conflicts with other signals.
About the Canonical Tag Checker
The canonical tag (<link rel="canonical" href="…">) tells search engines which URL is the main version of a page when the same content is reachable at several addresses – with and without www, with tracking parameters, sorted or filtered views, or printer-friendly copies. It consolidates ranking signals onto one URL.
Canonical mistakes are silent but costly: pointing every page at the homepage, pointing to a redirected or 404 URL, or sending mixed signals with noindex can drop pages out of the index. This checker reads both the HTML tag and the HTTP header, verifies that the canonical URL actually loads, and compares it with og:url and robots directives.
Frequently asked questions
Should every page have a canonical tag?
Yes. A self-referencing canonical on every indexable page is a cheap safeguard against duplicate URLs created by parameters and tracking codes.
Is a canonical a directive or a hint?
It is a strong hint. Google usually follows it, but may choose a different URL if other signals (redirects, internal links, sitemaps) point elsewhere.
Canonical or 301 redirect?
Use a 301 when the old URL should no longer be visited. Use a canonical when both URLs must keep working for users, for example filtered product listings.