Canonical Tag Checker
A canonical tag tells search engines which URL to index. Aimed at the wrong URL it quietly removes a page from search, and nothing in a browser shows it. This check reads the canonical on the homepage and a sample of internal pages and reports the cases that cost indexing.
Results open in the site's full report, which you can share, compare and re-run.
What it checks
- Whether each checked page has a canonical tag at all
- Canonicals pointing to another origin
- Canonicals pointing at a different page on the same site, the usual cause of a page silently dropping out
- noindex combined with a canonical elsewhere, which are contradictory instructions
- Malformed canonical URLs
Frequently asked questions
- Should every page have a canonical tag?
- Every indexable page should have a self-referential one. It costs nothing and it stops parameter and tracking variants of the URL from competing with each other.
- Is it bad to canonicalise to a different page?
- Only if you did not mean to. It is correct for genuine duplicates, and a mistake when a template hardcodes one URL across a section — then every page in that section asks to be dropped in favour of one.
- Why is noindex plus a canonical a problem?
- They say different things: noindex asks for the page to be dropped, a canonical asks for a different URL to be indexed in its place. Google treats the combination as a contradictory signal and may honour either one.
- How many pages are checked?
- Up to twelve same-origin HTML pages, found from the sitemap and homepage links. It is a sample, not a full crawl.
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