What is a Canonical URL?

A canonical URL is the preferred version of a page, which you pass on to search engines with a canonical tag. When the same or similar content can be reached at several URLs, the canonical prevents Google from seeing them as duplicate content and consolidates the SEO value on one version.

What is a canonical URL for?

Many websites show the same content at several URLs, for example because of filters, sorting options or tracking parameters. With a canonical tag you point out the main URL. That way Google knows which version to index and show, and the value is not split across variants.

Canonical and duplicate content

Duplicate content can weaken your visibility because search engines do not know which page to rank. A correct canonical solves that by linking the variants to the preferred version. It is an important part of technical SEO.

Common mistakes

Make sure the canonical points to an existing, indexable page and not accidentally to the wrong URL. A canonical that refers to a blocked or non-indexed page gives search engines conflicting signals.

Is a canonical a redirect?

No. A redirect sends visitors on to another URL, while a canonical indicates a preference without moving the visitor.

Should every page have a canonical?

A self-referencing canonical (one that points to the page itself) is a safe, common default.