Search basics
Canonical URL
The address Google treats as the main version of a page that can be reached at several. You can suggest one; Google makes the choice.
Also called rel=canonical, canonical tag · Sources checked 15 November 2026
The same content often lives at more than one address: with and without www, with tracking parameters, under two categories. Google picks one as canonical, shows that one in results and consolidates signals on it.
You influence the choice with signals, which Google's documentation ranks by strength. A redirect is a strong signal. A rel="canonical" link in the page head is a strong signal. Listing the address in your sitemap is a weak one. They add up, so using more than one makes your choice more likely to stick.