Canonical Tag Auditor
Check whether your canonical tags are configured correctly and pointing where you think they are.
Audit a URL
Results
Enter a URL and the canonical audit appears here: what the tag says, where it points, and every way it could be ignored.
How to use it
- Paste a URL and hit Audit. The page is fetched server-side and followed through any redirects, so what gets audited is the page a crawler actually lands on.
- Read the banner first. It answers the only question that matters up front: does this page keep its own signals, hand them to another URL, or leave the choice to Google.
- Open Advanced options to name the canonical you expected. The audit then says outright whether the page points there, which is the fastest way to verify a duplicate was set up correctly.
- Switch to Bulk URLs to run up to 20 at once. The table flags the type and issue count per URL, and any row expands into the full audit.
Getting canonicals right
- Every indexable page needs a self-referencing canonical, even one with no duplicates anywhere. It is what stops a tracking parameter or a session ID from spawning a second version of the page in the index.
- Canonical tags are a hint, not a directive. Google weighs them against internal links, sitemaps, hreflang and the content itself, and it overrules a canonical it does not believe. Search Console's Page indexing report tells you which URL it actually chose.
- Never pair a canonical with a noindex. The pair asks for opposite outcomes, and Google resolves it by dropping the page rather than consolidating it. Pick one.
- A canonical pointing at a URL that redirects is a chain, and chains get followed inconsistently. Point it at the final destination, not at the URL that will send a crawler there.
- Relative canonical hrefs resolve against whatever URL the page was served at, so the same template can produce a correct canonical on one address and a wrong one on another. Always write them absolute.
- HTTP Link header canonicals are the only option for files with no HTML to hold a tag: PDFs, images, feeds. They also work on HTML pages, but a page carrying both is asking for the two to drift apart.
- Paginated pages should canonicalise to themselves, not to page one. Google retired rel=next and rel=prev in 2019, and canonicalising page five to page one hides everything only page five links to.
Frequently asked questions
What is a canonical tag?
A canonical tag is a link element in a page's head that names the preferred URL for that content: <link rel="canonical" href="https://example.com/page" />. When the same or very similar content is reachable at more than one address, the tag tells search engines which address to index and consolidates the ranking signals from the others onto it. Without one, search engines still pick a canonical URL, they just pick it themselves using internal links, sitemaps and whichever variant they crawled first, and their choice is often a parameterised or uppercase variant you would not have chosen.
Should every page have a canonical tag?
Yes, and it should point at the page's own URL. A self-referencing canonical costs nothing and closes off the whole class of duplicate content that URLs create on their own: UTM parameters from a campaign, a session ID appended by the server, an affiliate tag, a trailing slash added by a link someone else built. Each of those is a distinct URL serving identical content, and each is a candidate for the index until a canonical says otherwise. The exception is a page you genuinely want consolidated elsewhere, where the canonical names the other URL instead.
What happens if my canonical points to a different page?
You are telling search engines the current page is a duplicate and the target is the version worth keeping. Signals from links pointing at the current URL get credited to the target, and the current URL usually drops out of the index in favour of it. That is exactly right for a printer-friendly variant or a parameterised URL, and badly wrong when it happens by accident, which is the usual outcome of a template hard-coding one canonical across a whole section. If pages are disappearing from the index without a noindex to explain it, a canonical pointing somewhere unintended is the first thing to check.
Can I use canonical tags across different domains?
Yes. Cross-domain canonicals are supported and are the standard way to handle syndication: the republished copy carries a canonical back to the original, so the original keeps the ranking. Google treats a cross-domain canonical as a weaker signal than a same-site one, because it cannot verify the two parties agree, and it may decline to follow it if the pages differ too much. It also will not help if the syndicating site refuses to add the tag, in which case a noindex on their copy is the fallback worth asking for.
Why is Google ignoring my canonical tag?
The common causes are mechanical and all detectable: more than one canonical tag on the page, a canonical placed outside the head, a relative href resolving to the wrong address, a canonical pointing at a URL that redirects or returns a 404, an HTML tag and an HTTP Link header naming different URLs, or a noindex sitting alongside it. Beyond those, Google simply disagrees: if the two pages are not close enough duplicates, or the canonical target is weaker on internal links and sitemap presence than the page pointing at it, it picks its own canonical and reports the choice in Search Console under "Duplicate, Google chose different canonical than user".