NightshiftDirect

Glossary

Canonical tag

A canonical tag is a link element in the head of a page, written rel="canonical", that names the preferred address when the same or very similar content can be reached at more than one address. Google weighs it as a strong signal when it picks which address to show.

Also called rel=canonical, canonical link element.

By NightshiftDirect Research. Published . Updated .

The signals Google weighs

The same page often answers at several addresses without anyone planning it: with and without www, with a tracking code on the end, or under two paths in your menu. Google treats those as duplicates and picks one to show. Redirects and canonical tags are strong signals of which one you prefer, and listing an address in your sitemap is a weak one. None is required, because Google chooses a version on its own when you state no preference (Google Search Central).

So on a small site a missing canonical tag rarely matters much. A wrong one can.

Why you might state one anyway

Two of the reasons Google gives matter most on a small site. The tag lets you choose which address people see in results, so searchers get your clean page address and not a variant with codes on the end. It also lets links be counted together: when other sites link to three versions of the same page, a canonical helps Google count those links toward the one you named (Google Search Central).

Mistakes that send Google the wrong way

Canonical tags usually come from a template, so one error repeats on every page that uses it. The tag might name another website entirely, left over from a page or theme copied from elsewhere. It might name a page that has since been deleted. Or it might name an old address that now redirects, so the tag and the redirect disagree about where the page lives.

The scan reads the canonical tag on every page it visits and flags those it finds pointing to another site, to an error page or to a redirect. That is T3, with examples as evidence. The fix is the same each time: give each page a canonical that names its own final https address.

Where redirects come in

When an old address should stop being used altogether, a redirect does more than a canonical tag, because it moves visitors as well as Google. A permanent redirect leads Google to show the new address in results (Google Search Central). A canonical tag suits pages that have to stay reachable at more than one address, as an ad landing page often does.

Keep the two in agreement. If page A redirects to page B, every canonical tag, internal link and sitemap entry on your site should name B.

What the free scan checks

Questions

Do I need a canonical tag on every page?

No. Google does not require one, and it picks an address itself when you name none. A tag on each page naming its own final address costs little, though, and a page whose tag does that never trips T3.

What about the tracking codes on my ad and email links?

One tag covers them all. An ad click or a newsletter link can add a code to the end of your address, but each variant loads the same page, and that page carries one canonical naming the clean address for Google to show (Google Search Central). Some templates build the canonical from the full address, code included, which names the variant instead. To check, open a variant and read the canonical line in its page source.

Where this fits in our work

We handle this as part of SEO: A written plan built from your own Search Console and Analytics data, then the fixes and pages that plan calls for, month by month.

Related reading

Related terms

Sources