Rapid Index Check

Canonical Checker

Check canonical tag consistency and detect canonicalization issues.

Free for up to 50 checks per day. No signup required.

Canonical diagnostics

Use the Canonical Checker when the wrong URL may be selected for indexing

Canonical tags are hints that tell search engines which version of similar pages should be treated as the primary URL. They are helpful for duplicates, parameters, and syndicated content, but incorrect canonicals can make the URL you care about disappear from search.

This checker helps you confirm whether the page points to itself, points to another URL, or has no canonical at all. That context is especially important for ecommerce filters, migrated pages, translated URLs, and CMS-generated duplicates.

Recommended workflow

If the page should rank on its own, use a self-referencing canonical. If it is a duplicate, make sure the canonical target is live, indexable, and internally linked. Recheck both source and target URLs after changing templates.

What this check reviews

  • Canonical URL found in the page source.
  • Whether the canonical is self-referencing.
  • HTTP status and redirect state of the submitted URL.
  • Other blockers, such as noindex or robots.txt rules.

Canonical patterns to investigate

  • A product or article page canonicalizes to the homepage.
  • HTTP and HTTPS versions disagree about the preferred URL.
  • Parameterized URLs create duplicate pages with inconsistent canonicals.
  • A migration leaves old pages canonicalized to outdated URLs.

Frequently Asked Questions

What does the Canonical Checker do?

This tool checks whether a URL has a canonical tag, whether it points to itself (self-canonical), or to a different URL. Canonical issues can cause indexing problems when the wrong URL is indexed.

What is a self-canonical?

A self-canonical is when a page's canonical tag points to itself. This is the recommended practice for indexable pages, as it tells search engines "this is the primary version of this page."

What happens if canonical points to another URL?

When a canonical tag points to a different URL, search engines may index the target URL instead of the current one. This is useful for duplicate content, but can cause issues if implemented incorrectly.

Can a missing canonical cause indexing issues?

A missing canonical tag is not necessarily a problem, but it removes an explicit signal to search engines about which URL is preferred. For pages with parameters, filters, or session IDs, a canonical tag helps consolidate indexing signals.