Canonical tag vs 301 redirect: which should I use?

Use a 301 redirect when the old URL should no longer be visited, and use a canonical tag when both URLs must stay reachable but one should be the version shown in search. A redirect moves the visitor. A canonical tag only tells search engines which address you prefer.

Why it matters

Both tools deal with several URLs showing the same or very similar content, but they behave differently. A redirect is a firm instruction that every visitor and crawler follows. A canonical tag is a hint that search engines usually follow but can overrule. Picking the wrong one either breaks a page people still need or leaves duplicates unresolved.

How to choose

Ask whether anyone needs the duplicate address to keep working as its own page. If not, redirect.
Use a 301 redirect for: a renamed or merged page, the www and non-www versions, http to https, a retired product page replaced by a new one and a site move to a new domain.
Use a canonical tag for: a page that appears with tracking or sort parameters, a printable version, a product reachable through several category paths and content you republish on a partner site.
Add the tag inside the head of each duplicate page:

<link rel="canonical" href="https://www.example.com/shoes/trail-runner/">

Add the redirect on the server for each old URL:

Redirect 301 /old-shoes /shoes

Do not combine them on the same URL. A redirected page never shows its own HTML, so a canonical tag on it is not read.
Test. The redirect should return 301 in curl, and the canonical should appear in the page source of the duplicate and in the URL Inspection tool in Google Search Console.

Common mistakes

Using a canonical tag where the duplicate page should simply be removed.
Redirecting parameter variants that visitors legitimately use, such as filters, and breaking the page.
Pointing a canonical tag at a URL that itself redirects.
Expecting a canonical tag to be obeyed when sitemaps, links and redirects all point somewhere else.
Using a canonical tag to move a whole site instead of redirects.

Frequently asked questions

Which is stronger?

A redirect is enforced for every request, so the visitor and the crawler both end up at the target. Google lists both redirects and the rel="canonical" tag among its canonicalization signals, but only the redirect changes where people actually land.

Can a page have both?

Not usefully on the same URL. You can have redirects for some addresses and canonical tags on others, but a redirecting URL does not deliver a page that could carry a tag.

What if I cannot edit server settings?

Use the canonical tag, which can be set from most CMS templates or SEO plugins, and ask your host or developer about redirects when you can.

To see how your own pages handle duplicates, Try the free website sample.