Canonical Tag

Canonical Tag is an HTML link element that names the preferred version of a page when the same or very similar content is reachable at more than one URL.

Placed in the page head as <link rel="canonical" href="...">, it points to the URL you want search engines to treat as the master copy. When duplicate or near-duplicate pages exist, the tag tells engines to consolidate their signals onto the chosen URL rather than splitting relevance across several addresses. A page can declare itself canonical by pointing the tag at its own URL.

It is important to understand that the canonical tag is a hint, not a directive. Search engines treat it as a strong suggestion but may pick a different canonical if other signals, such as internal links, sitemaps, or redirects, point elsewhere. So the tag works best when it agrees with the rest of your signals rather than fighting them.

Common uses include parameter URLs (tracking codes, sort and filter variants), printer-friendly versions, syndicated content pointing back to the original, and pagination handling. A few rules keep it reliable: point to one canonical URL, use absolute URLs, and do not canonicalise a page to one that is noindexed or redirected. Where you need to guarantee a page stays out of the index, the canonical tag is the wrong tool; a noindex directive keeps it out, while the canonical only consolidates. For deeper handling of duplicates, see the duplicate content guide.

<link rel="canonical" href="https://example.com/product/olive-oil/">

Related: Duplicate Content Guide, Indexation Checks, 301 Redirect