Canonical Tag Checker
Paste your page HTML source to detect canonical link tags, identify canonical URL, and flag common canonical issues.
About Canonical Tag Checker
Canonical tags (<link rel="canonical">) tell search engines which URL is the preferred version of a page, preventing duplicate content issues. This tool detects all canonical tags in your HTML source and flags common problems.
Common Canonical Issues
- Missing canonical — Pages without a canonical tag may suffer from duplicate content dilution.
- Multiple canonicals — Only one canonical tag should exist per page; multiple tags are ignored or cause confusion.
- Relative URL — Canonical URLs should be absolute (starting with https://).
- Canonical to a different page — If not self-referencing, this page is pointing its SEO value to another URL.
Best practice is to include a self-referencing canonical on every page. This explicitly signals the preferred URL and prevents issues with URL parameter variations (e.g. ?utm_source=...) being treated as duplicates.