301 Redirect: Permanent Redirect

What is a 301 redirect

A 301 redirect is an HTTP status code 'Moved Permanently' that tells browsers and search engine crawlers: 'The requested resource has been permanently moved to a new URL.' Unlike temporary redirects (302, 307), a 301 transfers nearly all link equity (link juice) from the old page to the new one and updates search engine indexes.

For SEO, this is the most important redirect type. When used correctly, 301 helps preserve rankings and traffic during any site structure changes: migrating from HTTP to HTTPS, consolidating www vs non-www, changing CMS, removing old sections, or merging pages.

When to use 301

• Site migration to a new domain (e.g., old domain → new brand domain).
• Switching from HTTP to HTTPS (set up 301 from each HTTP URL to its HTTPS version).
• Canonicalizing domain mirrors: redirect www to non-www (or opposite).
• Changing URL structure: renaming categories, creating clean URLs from dynamic ones.
• Removing pages while preserving traffic: redirect old URL to the most relevant existing page.
• Consolidating duplicates: several similar pages → one canonical page.

Impact on SEO and link equity transfer

According to Google's tests and statements, a 301 redirect passes 90–99% of link equity. This means external links pointing to the old URL will work almost fully for the new address. However, the transfer isn't instant: Googlebot must recrawl the chain and update its index, which can take from days to weeks.

Some metrics (e.g., page age, link history) may reset after a redirect, so major migrations often cause temporary ranking fluctuations. To minimize losses, use page-to-page redirects (old URL → exactly one new URL), avoid mass 301s to the homepage, and implement redirects at the server level (not via JavaScript or meta refresh).

How to set up a 301 redirect

The setup method depends on your server environment. Here are examples for popular platforms:

# .htaccess (Apache)
Redirect 301 /old-page https://example.com/new-page

# or with mod_rewrite for batch rules:
RewriteEngine On
RewriteRule ^old-folder/(.*)$ https://example.com/new-folder/$1 [R=301,L]

# Nginx
server {
    location /old-page {
        return 301 https://example.com/new-page;
    }
}

<?php
header("HTTP/1.1 301 Moved Permanently");
header("Location: https://example.com/new-page");
exit();
?>

After setting up, test redirects using tools: Google Search Console (Coverage → 'Page with redirect'), Screaming Frog, or online HTTP status checkers.