FREE TOOL / NO ACCOUNT / RUNS ON THE PAGE YOU GIVE IT
Canonical tag checker
Does your canonical match the URL you actually land on after redirects, does it point at itself, is it absolute, and is the page it names even real. Four questions, one request.
We follow the redirects first, because the canonical has to match the URL you actually land on, not the one you typed. Then we request the canonical target to see whether it is real.
QUESTIONS ABOUT THIS TOOL
- What does self-referencing mean, and do I need it?
- A self-referencing canonical is a page naming its own URL as the real one. Google does not require it, but it is the cheapest defence against duplicates: any version of the page reachable with a tracking parameter, a session id or a different trailing slash still points back at one address.
- Why does the canonical have to match the URL after redirects?
- Because the URL after redirects is the one search engines index. If /page redirects to /page/ and /page/ still declares /page as canonical, you have told Google the real version is an address that immediately sends it somewhere else.
- Does the canonical have to be an absolute URL?
- Google's documentation says to use the full address including the scheme and domain. Relative canonicals are read, but they resolve against the current URL, so the same tag means different things on different paths and breaks the moment a page is served from somewhere unexpected.
- What is a canonical chain?
- Page A says B is canonical, and B says C is canonical. Google follows one step, not a chain, so A's signal can be dropped. Point A directly at C.
- Can a canonical be set outside the HTML?
- Yes. An HTTP Link header with rel="canonical" works, and is the usual way to canonicalise a PDF or an image. We read the header as well as the tag, and say which one we found.
A TOOL CHECKS ONCE. SEOBUILDER KEEPS WATCH.
We can watch this for you.
A canonical usually breaks in a template, which means it breaks on every page at once and no single page looks wrong. We check yours across the whole site on a schedule and tell you when one starts pointing somewhere new.