Canonical URL Checker

Detect and validate the canonical URL tag in your HTML head section.

Paste the <head> section of your page to check for the canonical link tag.

How To Use

  1. Copy Your HTML — Open your webpage source and copy the <head> section.
  2. Optional: Add Expected URL — Enter the URL you expect the canonical tag to point to.
  3. Check & Validate — Click "Check Canonical Tag" to detect, validate, and compare.

What Is a Canonical URL?

A canonical URL (specified via <link rel="canonical">) tells search engines which version of a page is the preferred or "master" version when multiple URLs contain similar or identical content. This is essential for preventing duplicate content issues, which can dilute your ranking signals across multiple URLs. For example, if your page is accessible at both https://example.com/page/ and https://example.com/page?ref=home, the canonical tag tells Google which one to index and rank.

When to Use Canonical Tags

Use canonical tags whenever you have duplicate or near-duplicate content across different URLs. Common scenarios include printer-friendly versions of pages, session IDs in URLs, URL parameters for tracking or sorting, HTTP vs HTTPS versions (before full migration), www vs non-www variations, syndicated content republished on other sites, and paginated content where you want to consolidate ranking signals. A well-implemented canonical strategy prevents search engines from splitting your SEO value across multiple similar pages.

Canonical Tag Best Practices

Always use absolute URLs (not relative) in your canonical href attribute. Use only one canonical tag per page — multiple tags can confuse search engines. The canonical URL should point to a page that actually exists and returns a 200 status code (not a redirect or 404). Use self-referencing canonicals (pointing to the page itself) as a best practice even when there's only one version of the page. Test your canonicals regularly with this tool to ensure they haven't been accidentally removed or misconfigured during site updates.

Why Use This Canonical Checker?

This tool analyzes your HTML head section and detects the canonical link tag. It shows you the detected URL, validates its format, and optionally compares it against your expected URL to flag mismatches. Everything runs locally in your browser — your page markup stays private. No server uploads, no data logging, no limits.