canonical tag checker

A canonical tag expresses which URL you prefer search engines to treat as the representative version of duplicate or very similar content. It is a strong signal, not a guarantee. Enter a URL above and the check reports the canonical the page actually declares in the HTML and HTTP headers, so you can review whether those signals are consistent.

Why this is the quiet cause of lost rankings

Nothing about a mistaken canonical is necessarily visible to a visitor. It may come from a template that hardcodes one URL across a section, a staging URL left after launch, or two systems emitting conflicting values. Because canonicalization also considers redirects, internal links, sitemap inclusion, and content similarity, review the whole set of signals rather than treating a single tag as a final instruction.

Conflicting signals are worse than a missing tag

Using an HTML canonical and an HTTP-header canonical is supported, but it is more error-prone because the values can drift. Conflicting signals, a redirecting target, or a target that does not closely match the content reduce the clarity of your preference. Keep canonical-related signals consistent so search engines can evaluate the intended representative URL.

What correct looks like

Use a self-referential canonical on the preferred HTML page. For duplicate parameterized or filtered URLs, point at the clean representative version when the content is genuinely the same. Paginated pages generally canonicalize to themselves. Prefer an absolute HTTPS URL and keep its host, path, redirects, internal links, and sitemap entries consistent. Choose either HTML or HTTP headers where practical; if you use both, make their values identical.

Canonicals and redirects solve different cases

Use a permanent redirect when you are retiring a duplicate URL. Use a canonical when duplicate URLs need to remain reachable. Both are canonicalization signals, so they work best when the preferred target is consistent across your site.