301 redirect – what it is and how it affects your SEO

Definition

A 301 redirect is a permanent redirect that tells browsers and search engines that a URL has moved to a new address – and that the change is final.

What does status code 301 mean?

When a user or search engine requests a URL with a 301 redirect, the server responds with HTTP status code 301 (Moved Permanently). The browser sends the visitor straight on to the new address, and search engines such as Google take it as a sign that the old URL has been retired for good and replaced by the new one. This is what separates a 301 from a 302 redirect (Found/Temporary): a 302 says the move is temporary and that the original URL should stay in the index.

How much link juice is passed on?

A 301 redirect passes most of a page's authority and link equity (PageRank) to the new URL. According to Google Developers, Google now treats 301 and 302 redirects as broadly equivalent when it comes to passing link value, but standard practice is still to use a 301 for permanent changes, because it sends a clear signal. The link value built up from external backlinks, internal links and past rankings carries over to the new URL.

When should you use a 301 redirect?

• Domain change – When the website moves to a new address, for example from olddomain.com to newdomain.com. Every old URL is redirected to its new equivalent.
• HTTP to HTTPS – Redirecting from insecure HTTP to encrypted HTTPS is now a basic requirement for any website.
• URL restructuring – If you change your URL structure, for example from /blog/2024/title to /blog/title, 301 redirects preserve the rankings the old links have earned.
• Merging pages – When two similar pages are combined into one, a 301 redirect sends visitors from the retired page to the one that stays.
• Removing www or a trailing slash – Canonical URL normalisation, for example so that www.example.com and example.com always resolve to the same address.

301 redirect vs 302 redirect

The choice between 301 and 302 affects how search engines index and cache pages:

• 301 (Permanent) – Use when the move is final. Search engines replace the old URL with the new one in the index and pass on link equity.
• 302 (Temporary) – Use for A/B tests, temporary campaign pages or maintenance mode, for example. Search engines keep the original URL in the index.

Common SEO mistakes with 301 redirects

• Redirect chains – A → B → C instead of A → C. Every extra hop wastes crawl budget and can reduce the link equity that gets passed on. Keep chains as short as possible.
• Redirecting to the homepage – Sending every removed page to / rather than to a relevant new page signals a "soft 404", and the link equity is lost.
• Forgotten internal links – A 301 protects the link equity from external links, but you should still update internal links to the new URL to avoid unnecessary redirect hops.
• Missing HTTPS redirect – If both the HTTP and HTTPS versions of the website can be reached without a redirect, you end up with duplicate content.