Duplicate content and canonical URLs

When the same or very similar content is available at several URLs, Google groups them and shows one, the canonical URL. If you do not say which one you prefer, Google picks.

Common causes

Cause	Example
Protocol and host	http://, https://, www. and bare-domain versions all answer
Trailing slash and case	/batai and /batai/, /Batai/
Parameters	?sort=price, ?utm_source=facebook, ?page=1
Products in several categories	/vyrams/batai/x and /zygiams/batai/x
Print or mobile versions	/print/, m.example.com
Copied text across pages	The same description on 50 product variants

Ways to state your preference

Google lists these methods, from strongest to weakest:

1. Redirects: a strong signal. Use them when the duplicate URL should not be visited at all, for example for http to https, non-www to www, or old to new URLs.
2. rel="canonical": a strong signal. Use it when both URLs must keep working, for example with tracking parameters, sorting or variant URLs.
3. Sitemap inclusion: a weak signal. List only canonical URLs in your sitemap.

The methods can be combined, and they work best when they all agree.

<!-- On https://example.com/batai/?sort=price -->
<link rel="canonical" href="https://example.com/batai/">

Self-referencing canonicals

Most sites add a canonical that points to the page itself on every indexable page. That protects against parameter variants, for example when someone links to the page with a tracking parameter. Use absolute URLs.

Check what Google chose

In Search Console's URL Inspection, compare the user-declared canonical with the Google-selected canonical. If they differ, check whether your other signals disagree:

• Internal links point to a different version.
• The sitemap lists a different version.
• Redirects or hreflang point elsewhere.
• The two pages are not really duplicates, for example a filtered category with different products.

Thin variations across many pages

When many pages share almost the same text, such as 40 product variants with one copied description or one page per town with only the town name changed, canonicals are not the main fix. Consider whether the pages need to exist separately. Write genuinely different content for the ones that do, and consolidate the rest. Mass-produced near-duplicate pages made to rank can fall under Google's scaled content abuse policy.