Try it yourself
A visitor has filtered a shop page, so they are on https://millbrook-bakery.example/breads?type=sourdough&sort=price — the same products as /breads, in a different order.
Which canonical tag should that page carry?
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Points at the right page, but a relative canonical is fragile — it resolves against whatever address the page happens to be served at. The specification allows it; every piece of advice you will read says use the full URL anyway.
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This is the one. It says: this filtered view is a version of /breads, so please count them as one page and index that one. Absolute, unambiguous, and it stops every filter combination competing with itself.
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The page declaring itself the original. Now every combination of filter and sort order is its own page, and one shop section quietly becomes forty near-identical ones.
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Points at the homepage, which tells Google this page is not worth indexing on its own. A surprisingly common setting in themes that offer "canonical to homepage" as though it were a shortcut.
Pick a line. Every one of them has an answer.
Show me the answer
<link rel="canonical" href="https://millbrook-bakery.example/breads">
This is the one. It says: this filtered view is a version of /breads, so please count them as one page and index that one. Absolute, unambiguous, and it stops every filter combination competing with itself.
The written version
Canonical tags: naming the real address of a page →
How to check your own site for this, what to change, and how to confirm it worked.
Now the real thing
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