Canonical differs on mobile: how to fix it

What it means

The canonical URL declared on the mobile version of the page is different from the one on the desktop version. This usually means the mobile page points to a separate canonical URL instead of pointing to the same URL as desktop.

Why it matters

Google indexes and ranks using the canonical URL, so mismatched canonicals split ranking signals between two URLs. Mobile-first indexing means the mobile version's canonical is the one that matters most for ranking. If the canonicals diverge, the wrong URL may appear in search results and AI crawlers may fetch different content from the same page.

How to fix it

1. Set a single self-referencing canonical on every page version: <link rel="canonical" href="https://example.com/page">.
2. Verify both mobile and desktop return the same canonical URL in the HTTP response headers and in the HTML source.
3. If using responsive design with a single URL, remove any version-specific canonical overrides.
4. Check that the canonical URL is not blocked in robots.txt or marked noindex.

Example

<!-- desktop -->
<link rel="canonical" href="https://example.com/page">

<!-- mobile (m.example.com) -->
<link rel="canonical" href="https://m.example.com/page">

<!-- both desktop and mobile canonicalize to the same URL -->
<link rel="canonical" href="https://example.com/page">

Mobile and desktop must declare the same canonical. On a separate m. site, the mobile page canonicals to the desktop URL and the desktop page adds rel=alternate media pointing to mobile.

When it's not a problem

This is fine if the mobile and desktop pages intentionally serve different content (for example, a simplified mobile view with its own canonical) and both versions are meant to be indexed separately. It is also acceptable when the canonicals differ only in trailing slashes or HTTP versus HTTPS, which Google treats as equivalent.

How Crawlinx detects it

We fetch the page with a mobile user-agent and compare its rel=canonical to the desktop crawl's, normalizing the URLs. A disagreement is reported with both values, since a shifting canonical confuses mobile-first indexing.

How common is it?

Not yet observed in our audit sample. We publish this explainer because the check runs on every crawl; once an audited site trips it, this page will break the issue down by platform, gatekeeper, vertical and country.

FAQ

Should mobile and desktop canonicals match?

Yes. Both versions should point to a single canonical URL. Under mobile-first indexing a canonical that changes between versions gives Google conflicting consolidation signals.

How do I set canonicals with a separate m. site?

The mobile page's canonical points to the desktop URL; the desktop page adds <link rel="alternate" media="..." href="[mobile URL]">. That's the documented separate-URLs pattern.

Is a responsive site immune to this?

Usually — one URL, one canonical. It can still trip if a mobile-only script rewrites the canonical, so verify the rendered mobile DOM, not just the source.

Related guides

• Mobile-First Indexing: How to Pass Parity Checks