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Bulk up to 100 • HTML + header canonicals

Canonical Tag Checker

Paste URLs — we’ll detect canonical signals from <link rel="canonical"> and HTTP Link headers, then flag missing, multiple, non-self, and cross-domain canonicals.

Paste up to 100 URLs (one per line)
Tip: multiple canonical tags or a canonical pointing elsewhere can confuse consolidation and slow indexing.

Results

URL Canonical HTTP Time Issues
Run a check to see results here.
“Non-self canonical” means the page points to a different canonical URL (can be valid, but check intent).

What to aim for

Canonical should match your intended “main” version.

  • OK one canonical, self-referencing (for indexable pages)
  • Warning missing/multiple/non-self/cross-domain/relative
  • Error HTTP/fetch errors or redirect loops
Canonicalization

Canonical Tag Checker: consolidate duplicates safely

Canonical tags tell search engines which URL should be treated as the primary version when duplicates exist. This checker finds canonical tags in HTML and in HTTP headers, then highlights issues that commonly break consolidation.

Common canonical problems

  • Missing canonical: duplicates can split signals across variants.
  • Multiple canonicals: conflicting signals inside the same document.
  • Non-self canonical: the page points elsewhere (sometimes intended, often accidental).
  • Cross-domain: canonical points to a different host.

FAQ

What does a canonical tag do?

A canonical tag tells search engines which URL should be treated as the primary version when multiple pages are similar or duplicated. It helps consolidate ranking signals and avoid duplicate-content indexing issues.

Does this tool check canonicals in HTML and HTTP headers?

Yes. It detects <link rel="canonical"> inside HTML and also checks the HTTP Link header when it includes rel="canonical".

What does “missing canonical” mean?

It means the page doesn’t provide a canonical signal in HTML or headers. For indexable pages, having a single intended canonical helps avoid accidental duplication across variants.

What does “multiple canonicals” mean?

It means more than one canonical was found (for example multiple <link rel="canonical"> tags). Conflicting canonicals can reduce trust in your signals and cause inconsistent indexing.

Is a “non-self canonical” always bad?

Not always. A page may intentionally canonicalize to another URL (for duplicates, parameters, printer versions, etc.). But if it’s not intentional, it can cause the page to be ignored in favor of the canonical target.

What is a cross-domain canonical?

A cross-domain canonical points to a different host (domain). This can be valid (syndication) but is risky if set by mistake — it may transfer canonical preference to the other domain.

Why does the tool warn about a relative canonical?

A relative canonical uses a path like /page instead of a full URL. Many setups handle it fine, but absolute canonicals are safer across redirects, proxies, and mixed environments.

Should the canonical target return HTTP 200?

Ideally, yes. Canonicals pointing to 4xx/5xx or unreachable URLs are a strong quality signal problem. This tool performs a quick status check of the canonical target when possible.