A wrong canonical can quietly deindex pages or split your ranking signals. Check your homepage's canonical instantly - no signup - then crawl every page.
Instant, free, no account needed - homepage checked on the spot.
The instant check reads your homepage's canonical. A full crawl checks every page's canonical against the rules below.
Every indexable page should declare a rel="canonical".
The canonical should point to the page's own clean URL unless you intend otherwise.
The canonical target must be a live page - not a redirect or a 404.
Flags canonicals that point at a URL which then redirects - a wasted signal.
Canonicals should use https, not leftover http after a migration.
A full audit tracks pages whose canonical changed between crawls.
Canonicalisation is subtle but high-impact - these are the rules that keep your ranking signals where they belong.
On every indexable page, add <link rel="canonical" href="THIS-PAGE-CLEAN-URL"> pointing to its own URL. This is the safe default and stops search engines guessing which of several similar URLs to index.
The URL in your canonical must be live and canonical itself - not a redirect, not a 404. A canonical pointing at a redirected URL is ignored, and Google picks its own. Re-check after any HTTP→HTTPS or trailing-slash change.
A common template bug: every page in a paginated series canonicalises back to page 1, which deindexes pages 2+. Each paginated page should self-reference (or use proper pagination handling), not point to page 1.
Your canonical, your hreflang annotations, and the URLs you link internally should all point at the same canonical version. Mixed signals (linking to one URL but canonicalising to another) confuse crawlers.
Canonical is a hint for consolidating duplicates - it is not a way to deindex a page (use noindex for that) or to block crawling (use robots.txt). Use the right tool for each job.
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 letting them split across variants, which is what prevents duplicate-content dilution.
It is a hint rather than a directive. Search engines usually respect a clear, consistent canonical, but they will override one that contradicts your other signals.
Every indexable page should carry a self-referencing canonical pointing at its own clean URL. That is the safe default and it removes the guesswork about which of several similar URLs to index. The exception is a page you deliberately want consolidated into another, in which case the canonical points at that target instead.
A canonical-to-redirect error is a canonical that points at a URL which then redirects, or that 404s outright. Google ignores the tag and picks a canonical of its own, so the signal you intended is simply lost. Every canonical must resolve to a live 200 URL, and this is worth re-checking after any HTTP to HTTPS migration or trailing-slash change, which are the usual sources of the problem.
The instant check above reads your homepage's canonical with no signup. To cover the rest, run a full audit, which checks every page's canonical for presence, self-reference, HTTPS, a live 200 target, canonical-to-redirect problems, and changes between crawls so you can spot a template edit that quietly rewrote canonicals site-wide.
Read the mechanics behind a check, or run the next tool on the same site.
Read the guide
How rel=canonical works and the mistakes that quietly deindex pages.
How canonicals resolve duplicate and near-duplicate URLs.
When to use noindex versus canonical, and how they differ.
Run another check
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