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Robots & crawl control

Canonical vs noindex: which to use

rel=canonical and noindex are often confused. Canonical tells search engines which of several similar URLs to treat as the primary, consolidating signals onto it. noindex removes a page from the index entirely. This page explains when each is right and why combining them on one URL sends conflicting signals.

Verified against primary sources

Two different jobs

rel=canonical is a consolidation signal: when several URLs serve the same or very similar content, it tells search engines which one to treat as primary so ranking signals concentrate there. The non-canonical duplicates are not removed from the web — their signals are merged onto the canonical.

noindex is a removal signal: it asks search engines to keep that specific page out of the index entirely. Use canonical for duplication, noindex for 'this page should not be in search at all.'

Why not to combine them wrongly

Putting noindex and a canonical pointing elsewhere on the same URL sends mixed signals: canonical says 'consolidate onto that other URL' while noindex says 'drop this one.' Google advises against combining conflicting signals, because the engine may interpret them unpredictably.

Choose based on intent. If two URLs are duplicates and you want one indexed, canonicalise to it and leave both crawlable. If a page should never appear in search, noindex it and keep it crawlable so the signal is read — do not also canonicalise it elsewhere.

How it appears in analytics and logs

A canonicalised URL should pass signals to its canonical and may still be crawled; a noindexed URL should drop from search. Mixing the two on one URL gives the engine contradictory instructions.

Diagnostic use case

Decide between consolidating duplicate URLs onto a canonical and removing a page from search with noindex, and avoid putting both on the same URL.

What WebmasterID can help detect

WebmasterID shows whether crawlers still fetch a URL, which is the prerequisite for either a canonical or a noindex signal to be read and acted on.

Common mistakes

Privacy and accuracy notes

Both are public indexing signals, not access control. Neither hides a page from someone with the link; private content needs authentication.

Related pages

Sources and verification notes

Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.