Search optimisation
Canonical tag present
A canonical link element is present
What we check
A canonical link element is present
Why it matters
Without a canonical, duplicate versions of the page compete with each other.
How to fix it
Add <link rel="canonical" href="…"> pointing at the preferred URL.
How it affects your score
This check sits in Search optimisation, which is worth 25% of the overall score. A critical result costs the full weight of the check; a warning costs half. If we can't measure it on your page, we leave it out of the score entirely.