Canonical tag
A canonical tag is an HTML element that tells search engines which URL is preferred when the same content is reachable at multiple addresses.
The canonical tag — <link rel="canonical" href="..."> — is a small HTML snippet in the page head telling search engines and AI engines which URL is the original source. Without it, duplicates cannibalise ranking signals. Used mostly for product variants, pagination, UTM parameters and syndication.
Example
A webshop has three URLs for the same red shoe. A canonical in each points to /red-shoe. All three pages consolidate their link equity onto one.
Frequently asked questions
Canonical tag or 301 redirect?
301 permanently redirects both users and engines. Canonical lets both URLs exist but hints to engines which to index. Use canonical for necessary duplicates, 301 for moves.
Related terms
Further reading
- → Our service: SEO