Canonical Tag

The same content can often be reached at several URLs — with tracking parameters, http vs https, trailing slashes, or print versions. To a search engine those look like separate pages competing with each other. A canonical tag placed in the page head names the one "master" URL you want ranked, so the duplicates hand their signals to it instead of splitting them.

Make your canonicals, internal links, and sitemap tell one consistent story: they should all point at the same preferred URLs. Self-reference the canonical on every important page (a page whose canonical points to itself). Use canonicals — not redirects — when both URLs must stay reachable for users but only one should rank, such as a product available under multiple category paths. Audit for the classic contradictions: canonical to A, sitemap lists B, internal links go to C.

Remember a canonical is a hint, not a directive — Google can and does override canonicals it disagrees with, especially when your other signals contradict them. So treat canonicalisation as signal hygiene across the whole site, not a per-page tag you sprinkle on. On large or syndicated content, decide deliberately whether you want to be the canonical source; cross-domain canonicals are how you cede or claim that authority.