Canonical tag

The same page often lives at several addresses without anyone planning it: with and without www, with a tracking code such as ?utm_source=newsletter added by an email tool, or a product reached from two categories. Google shows one of them in results and treats the others as copies.

A canonical tag says which one you want shown, so the links and signals the page earns add up on one address instead of being split. Google calls it a strong signal, not an order: if your sitemap or your own links point at a different address, it can pick that one instead. Google also recommends a canonical on the main page itself, pointing at its own address.

Most website builders and blog platforms write the tag for you, so on a small site the job is usually checking it, not writing it.

1. Open the page, view its source and search for canonical. You should find one tag, with the full https address of the page itself or of its main version.
2. In Google Search Console, paste the address into URL Inspection and compare the canonical you declared with the one Google selected.
3. In the Pages report, look at the pages listed as duplicates. Those are the addresses where Google chose a different main version than you, or found no canonical at all. Our guide to why a site is not on Google covers the rest of that report.

• Every page pointing its canonical at the home page, so Google treats them all as copies of it.
• A canonical that points at an address which redirects or no longer exists.
• Two different canonicals on one page, often one from the theme and one from a plugin.
• Using robots.txt to hide the copies. Google advises against it: a blocked address can still be indexed, just without its content.