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Canonical Checker

Paste a page’s HTML to extract and validate the rel="canonical" link tag. This checker flags common issues (missing/multiple canonicals, invalid or relative URLs, cross-domain targets, tracking params, fragments) without any network requests.

Category: SEO · URL: /tools/canonical-checker.html
Offline
No network calls
Tip: If your canonical is like /product, provide the page URL to resolve it.
Related: Meta Generator · Schema Tool Checker · UTM Checker 
Paste HTML and click Analyze.
Output is compact for easy copy/paste into tickets and audits.
Privacy: runs locally in your browser. No uploads, no tracking scripts.

How to use

Use it to quickly audit a page’s canonical setup from source code.

  1. Paste the page HTML into the input box.
  2. (Optional) Add the page URL to resolve relative canonicals.
  3. Click Analyze to see the canonical URL and any issues.
  4. Use Copy Output to share the result.
Keywords this page targets (natural cluster): canonical checker, check canonical tag, rel canonical validator, canonical url checker, find canonical in html, multiple canonical tags check, missing canonical tag check, canonical link tag test, validate canonical url format, relative canonical url resolver, canonical points to different domain, canonical with utm parameters, canonical with fragment hash, canonical vs page url compare, html canonical extractor, canonical tag audit, self-referencing canonical check, canonical tag best practice check, canonicalization checker, canonical link rel analyzer
Secondary intents covered: Extract the canonical URL from pasted HTML, Confirm whether a page has a canonical tag, Detect multiple canonical tags and conflicting href values, Resolve relative canonical URLs against a provided page URL, Validate canonical URL syntax and flag fragments/tracking parameters, Check whether canonical points cross-domain compared to the page URL, Spot conflicts like canonical + meta robots noindex, Generate a quick pasteable report for QA or SEO audits

FAQ

What does this canonical checker do?

It extracts the link rel="canonical" tag from pasted HTML and flags common problems like missing, multiple, invalid, or relative canonicals.

Does it fetch my URL or crawl my site?

No—everything runs locally in your browser and there are no network requests.

Why should I provide a Page URL?

It lets the tool resolve relative canonicals (like /page) into a full absolute URL for validation.

What if there are multiple canonical tags?

The tool marks it as a failure and warns if the href values conflict; pages should have only one canonical.

Is a cross-domain canonical always wrong?

Not always, but it’s a strong signal and should be intentional (e.g., syndicated content); the tool flags it as a warning when a page URL is provided.

Should canonicals include UTM parameters or fragments?

Usually no—tracking params and # fragments can undermine canonicalization, so the tool warns when it detects them.

What about canonical with noindex?

If the HTML contains meta name="robots" with noindex, the tool warns because canonical alone won’t make a noindexed page indexable.