What is a canonical tag?

A canonical tag is an HTML element ( ) placed in the page's that tells search engines which URL is the preferred version of a page, preventing duplicate content issues.

When should I use a canonical tag?

Use canonical tags whenever the same or very similar content is accessible at multiple URLs — such as with/without www, HTTP vs HTTPS, URL parameters (e.g., ?sort=price), or paginated versions.

What is a self-referencing canonical?

A self-referencing canonical is when a page's canonical tag points to its own URL. This is recommended best practice for original pages — it explicitly confirms to Google that this URL is the definitive version.

Can canonical tags pass link equity?

Yes. When you canonicalise a duplicate page to the original, link equity (PageRank) from the duplicate flows to the canonical URL, consolidating ranking power.

What if I have both a canonical and a noindex tag?

Having both is contradictory. Noindex says 'don't index this page' while canonical says 'treat this as the master copy'. Google will typically respect noindex and ignore the canonical, which is usually not what you intend.

On Page Seo

Free

Canonical Tag Checker

Check canonical URL presence, self-referencing, absolute vs relative, and verify the canonical target returns 200.

Page URL

What is Canonical Tag Checker?

The Canonical Tag Checker verifies the canonical URL tag (rel="canonical") on any webpage. It checks whether the tag is present, whether it's self-referencing (pointing to the page itself), whether it conflicts with other signals, and whether it's correctly implemented in the HTML head section.

Canonical tags are essential for preventing duplicate content issues. When multiple URLs serve similar or identical content (e.g., with/without www, HTTP/HTTPS, pagination, tracking parameters), the canonical tag tells search engines which version is the "master" copy that should be indexed and receive link equity.

Why Use Canonical Tag Checker?

Without correct canonical tags, search engines may index duplicate versions of your pages, split link equity across multiple URLs, and choose the wrong version to rank. This can significantly dilute your SEO efforts. The canonical tag is one of the most powerful and most commonly misconfigured on-page SEO elements.

Key Features of Canonical Tag Checker

✓Detects presence or absence of canonical tag in page head
✓Validates that canonical URL matches the expected page URL
✓Identifies self-referencing canonicals vs. canonical to another page
✓Checks for multiple canonical tags (invalid — only one is allowed)
✓Flags HTTP to HTTPS canonical mismatches

How to Use Canonical Tag Checker

1
Enter the page URL
Paste the URL of the page you want to check into the canonical checker.
2
Run the check
Click 'Check Canonical Tag' to fetch the page and extract canonical tag data.
3
Review canonical status
See whether a canonical tag is present, its current value, and whether it's valid.
4
Check for issues
Look for missing tags, wrong canonical URLs, HTTP/HTTPS mismatches, or multiple canonicals.
5
Implement fixes
Add or correct the canonical tag in your CMS or theme, then re-run to verify.