Canonical URL Checker
Validate and generate canonical link elements for duplicate content control. Check URL format, normalise URLs and copy the ready-to-use HTML tag.
🔍 SEO Tools
Free
Browser-based
What is a Canonical URL?
A canonical URL is the preferred version of a page when multiple URLs display identical or very similar content. The <link rel="canonical"> tag tells Google which URL to index and pass link equity to, preventing duplicate content penalties.
Common Duplicate Content Causes
| Source | Example Variants |
|---|---|
| HTTP vs HTTPS | http://example.com vs https://example.com |
| www vs non-www | www.example.com vs example.com |
| Trailing slash | /page/ vs /page |
| Tracking parameters | ?utm_source=email&fbclid=xxx |
| Sorting/filtering | ?sort=price&color=blue |
| Session IDs | ?sessionid=abc123 |
Self-Referencing Canonicals
Every page should include a self-referencing canonical tag — a canonical tag that points to the page's own clean URL. This protects against scrapers sharing your content and signals your preferred URL even when no duplicate exists.