Canonical Tag – Avoid Duplicate Content in SEO
The Canonical Tag (<link rel="canonical">) is an HTML element placed in the <head> section of a web page. It tells search engines which version of a page should be treated as the “original” (canonical) one, helping to prevent indexing of duplicate or near-identical content.
Typical use cases:
- Pagination (e.g. /page/2, /page/3)
- Filtered or sorted product listings in e-commerce
- Tracking URLs with query parameters
- CMS issues that expose content under multiple URLs
Example:
<link rel="canonical" href="https://www.example.com/seo-checklist" />This line instructs Google to treat the specified URL as the preferred version, even if multiple similar pages exist.
Best Practices:
- Define only one canonical URL per page
- The canonical URL should be accessible, indexable, and content-equivalent
- Use self-referencing canonicals (pointing to the page itself) when appropriate
- The Canonical Tag does not replace redirects, but works alongside them
Note: Canonicals are treated as hints, not commands. If there’s conflicting information (e.g. sitemap says A, canonical says B), Google may choose its own canonical.
