Canonical checker — is your canonical tag right?

Quick answer: paste a URL and see whether it declares a canonical, whether that canonical is itself, and whether anything else on the page contradicts it.

What a canonical is for

A canonical names the URL you want indexed when the same content is reachable at more than one address. It is a hint, not an instruction, and search engines override it when the rest of the evidence disagrees.

That last point is the one worth internalising. If Search Console tells you Google chose a different canonical than you declared, the tag is not broken — it lost an argument. Something else on the site pointed harder in another direction: internal links, a sitemap entry, a redirect, or simply more inbound links to the other URL.

The contradictions that cost you

noindex plus canonical. The page asks to be excluded and simultaneously nominates itself as the indexable version of something. These want opposite outcomes, and the resolution is not predictable.

Redirect plus canonical pointing elsewhere. A redirect already answers the question of which URL wins. A canonical on the destination pointing somewhere third is a second, conflicting answer.

A canonical carrying a tracking parameter. This turns every campaign link into its own indexable page, which is the exact problem canonicals exist to prevent.

Canonical or redirect

Redirect when the old URL should stop existing for people. Canonicalise when both must stay reachable but only one should be indexed — filtered views, parameter variants, print pages.

Using a canonical where a redirect belongs leaves two live pages competing for the same query, and the one that wins is not reliably the one you would have picked.

On Shopify

Canonicals are set automatically and are usually right: a product reachable through several collection paths canonicalises to its main product URL. The failure to look for is a theme or app adding a second canonical tag to the same page. See canonical URL for the full definition, and the redirect checker if the URL is reached through a chain.