Canonical tags: how and when to use them
28/07/2026
If the same or similar content appears on several URLs, Google has to decide which version to rank — and that decision may not be the one you want. A canonical tag (rel="canonical") is how you clearly tell it: "this is the main version, assign all signals to it."
What a canonical tag actually does
It is a line in the <head> of the page: <link rel="canonical" href="https://mysite.com/product">. It consolidates signals (links, authority, relevance) from duplicates onto a single canonical address. Google treats it as a strong hint rather than a command — in 90%+ of cases it honors it when set consistently.
When a canonical is required
- URL parameters: filters and sorting (?color=black, ?sort=price) create dozens of variants of the same page.
- HTTP vs HTTPS, www vs non-www: the same page reachable on multiple address forms.
- A product in several categories: /shoes/nike and /nike/shoes lead to the same item.
- Print or AMP versions: alternative renderings of the same text.
- Syndication: when you publish the same article on another site as well.
The most common mistakes
A canonical pointing to a page blocked in robots.txt, canonical chains (A points to B, B to C), a canonical on a 404 or a redirect, and — worst of all — every page pointing to the homepage. Such errors can drop whole sections out of the index. On large sites this directly wastes crawl budget, so canonicals and your sitemap and robots.txt must stay aligned.
Canonical and related signals
A canonical is not a replacement for a 301 redirect — if a page has moved permanently, use a redirect. On multilingual sites the canonical works together with hreflang tags: each language version has its own self-canonical, and hreflang links them. For pagination, current best practice is that every page in the list has a self-canonical — more on that in the guide to pagination and SEO.
How to check
In Google Search Console the URL inspection tool shows the "user-declared" and "Google-selected" canonical — if they differ, you have a signal problem. On WordPress, plugins like Yoast or Rank Math set a self-canonical automatically, which covers most cases. Stable WordPress hosting with daily backups makes experimenting safe, and if you are still choosing a plan, see our plans.