What does a canonical tag do?

A rel="canonical" tag tells search engines which URL is the preferred version when similar or identical content is reachable at more than one address. It consolidates ranking signals onto a single URL instead of splitting them across duplicate variants like tracking-parameter and trailing-slash versions.

Which pages need a canonical tag?

Every indexable page should carry a self-referencing canonical pointing at its own clean URL. That is the safe default and removes the guesswork about which of several similar URLs to index. The exception is a page you deliberately want consolidated onto another, which should canonicalise to that target.

How do you get canonical tags right?

Make every indexable page self-reference its canonical, never point a canonical at a redirect, a 404, or an HTTP version of an HTTPS page, and keep canonicals stable over time. A canonical to a non-200 or redirected URL wastes the signal. The Kalenux canonical checker verifies all of these across your whole site.

Can two pages canonicalise to each other?

Yes, and it is a real bug called a canonical loop: page A points its canonical at page B, and page B points back at A. Neither reference resolves, so search engines are left to pick a canonical on their own.

Is a canonical tag the same as a redirect?

No. A redirect sends both users and crawlers to a different URL. A canonical is a hint read only by search engines: the original page still loads normally for a visitor, but crawlers are told which version to index and rank.

Canonical Tag Checker - Check rel=canonical Free

01A strong hint, not a directive

When several URLs show the same content, Google chooses one as canonical. Your rel="canonical" influences that choice but doesn’t guarantee it [1].

Redirects and rel=canonical are strong signals; sitemap inclusion is a weak one. Google gets the clearest picture when all of them agree [2].

KEY FACTGoogle can pick a different canonical than the one you declare, especially when signals conflict [1].

02Point at a live, final URL

A canonical should be an absolute URL that returns 200. Canonicals pointing at a redirect or an error are among the mistakes Google warns against [2].

Permanent redirects are themselves a strong canonical signal, so a canonical pointing at a URL that redirects elsewhere sends two conflicting messages [3].

03One method, one answer

Google advises against naming different canonicals for the same page through different methods, and against using robots.txt for canonicalisation [2].

For files without HTML, such as PDFs, the canonical can be sent as an HTTP Link header instead [2].

04Canonicals and hreflang together

Each language version in an hreflang cluster should point its canonical to itself, not to another language. Otherwise the alternates can be dropped [4].

To see which URL Google actually chose, use the URL Inspection tool in Search Console; it shows both the user-declared and the Google-selected canonical [5].

References

[1]What is URL canonicalization · Google Search Centraldevelopers.google.com/search/docs/crawling-indexing/canonicalization
[2]How to specify a canonical URL with rel="canonical" and other methods · Google Search Centraldevelopers.google.com/search/docs/crawling-indexing/consolidate-duplicate-urls
[3]Redirects and Google Search · Google Search Centraldevelopers.google.com/search/docs/crawling-indexing/301-redirects
[4]Tell Google about localized versions of your page · Google Search Centraldevelopers.google.com/search/docs/specialty/international/localized-versions
[5]URL Inspection tool · Search Console Helpsupport.google.com/webmasters/answer/9012289

CITE THIS PAGEKalenux. (2026). Canonical checker: verify rel=canonical on any page. Kalenux SEO Guide. Last reviewed 1 Oct 2026. kalenux.com.tr/seo-canonical-checker

Canonical CheckerOne preferred URL for every page.

Six addresses, one pair of shoes.

A hint, not a command.

One line, five details.

Where should this page point?

What Google documents about canonical URLs.

01A strong hint, not a directive

02Point at a live, final URL

03One method, one answer

04Canonicals and hreflang together

References

Keep checking.