What is a 301 Redirect? SEO Guide for Beginners

A 301 redirect is the HTTP 301 Moved Permanently status code, which tells both browsers and search engines that the requested resource has moved permanently to the URL named in the response's Location header. The status code is defined in RFC 9110 (HTTP Semantics) and documented by MDN. For SEO, Google treats a permanent redirect as a canonicalization signal: Googlebot follows the redirect and the indexing pipeline uses the redirect target as the canonical URL, so the new page shows in search results in place of the old one. Your accumulated backlinks and ranking signals are reassigned to the new location instead of being lost.

Why 301 Redirects Matter for SEO

Every time you change a URL, you risk losing the SEO value that page has accumulated. Backlinks pointing to the old URL, existing rankings, bookmarked pages from users, all of that value evaporates if you simply delete the old page and create a new one at a different URL.

A 301 redirect solves this by creating a bridge. When Googlebot or a user hits the old URL, they are automatically sent to the new one. Google understands that the move is permanent and uses the redirect as a signal to make the new URL canonical, reassigning the original page's ranking signals to it. There is no published percentage for how much "link equity" survives a permanent redirect. Google's own guidance is simply that a permanent redirect transfers signals to the target page, so any specific "95 percent" figure you see elsewhere is a third-party estimate, not a Google spec.

I have seen businesses lose 40-60% of their organic traffic overnight because they redesigned their site, changed their URL structure, and did not implement 301 redirects. All the authority those pages built over years was gone. When they finally added the redirects weeks later, it still took months to fully recover.

This is not just about site migrations. Any time you consolidate pages, change a slug, move content to a new section, or switch domains, you need 301 redirects to preserve your SEO investment.

How 301 Redirects Work

When a browser or crawler requests a URL that has a 301 redirect, the server responds with a 301 HTTP status code and a Location header pointing to the new URL. RFC 9110 says the server SHOULD include the Location header carrying the new permanent URI, and a user agent may use it for automatic redirection, which is why every practical 301 you will configure includes it. The browser then automatically follows the redirect and loads the new page. Users barely notice the redirect happening. Per the Fetch standard, a user agent that receives a 301 in response to a POST request is permitted to switch to the GET method for the follow-up request. When you need the method preserved exactly, the 308 Permanent Redirect status exists for that reason, because altering the method after a 308 is prohibited.

For search engines, the 301 signals that the old URL should be replaced with the new one in the index. Google's documentation states that a permanent redirect (301 or 308) shows the new redirect target in search results, while a temporary redirect (302 or 307) keeps the source page in results and is not used as a canonical signal. Over time, Google drops the old URL from search results and replaces it with the new destination, and links to other sites that pointed at your old URL get reassigned to the new one.

Redirect chains happen when one redirect points to another redirect, which points to another. For example, Page A redirects to Page B, which redirects to Page C. Each hop adds latency and slows crawling. Google states that Googlebot can follow up to 10 hops in a chain, but advises redirecting to the final destination directly. If that is not possible, Google says to keep the chain low, ideally no more than 3 and fewer than 5.

How to Improve 301 Redirects on Your Site

1. Create a redirect map before any URL changes - Before migrating, changing URL structures, or redesigning your site, build a spreadsheet mapping every old URL to its new destination. Use Screaming Frog to crawl your current site and export all URLs. Match each one to where it should point.

2. Implement redirects at the server level - Configure 301 redirects in your web server (Nginx, Apache) or hosting platform rather than using JavaScript redirects or meta refresh tags. Server-level redirects are the fastest and the ones Google respects most. In Nginx, use return 301 directives. In Apache, use Redirect permanent or RewriteRule in .htaccess.

3. Redirect to the most relevant page - Do not redirect everything to your homepage. If someone had a blog post at /old-blog/seo-tips and you now have it at /blog/seo-tips-guide, redirect to the new specific page. Redirecting to the homepage wastes the topical relevance of the original URL.

Common Mistakes to Avoid

• Using 302 redirects when you mean 301: A 302 is temporary and does not pass full link equity. If you are permanently moving a page, always use 301. I have seen CMS platforms default to 302 redirects, causing sites to lose ranking power on pages they thought were properly redirected.

Key Takeaways

• A 301 redirect permanently moves a page to a new URL, and Google uses it as a canonical signal to reassign the old page's ranking signals to the new one.
• Always implement 301 redirects when changing URLs, consolidating pages, or migrating to a new domain or URL structure.
• Redirect to the most relevant destination page, not the homepage. Specificity preserves topical relevance.
• Monitor Google Search Console after any URL changes to catch missed redirects before they impact your traffic.

In Practice

Say you moved an old AJAX guide to a new URL. A real 301 response looks exactly like this, taken from MDN's documented example. The browser requests the old path and the server answers with the status code, the Location header pointing at the new path, and a short body.

GET /en-US/docs/AJAX HTTP/2
Host: developer.mozilla.org
User-Agent: curl/8.6.0
Accept: */*

HTTP/2 301
cache-control: max-age=2592000,public
location: /en-US/docs/Learn_web_development/Core/Scripting/Network_requests
content-type: text/plain; charset=utf-8
content-length: 97

Moved Permanently. Redirecting to /en-US/docs/Learn_web_development/Core/Scripting/Network_requests

Two details worth noting. The cache-control: max-age=2592000 means the redirect is cacheable for 30 days, so clients remember the move without re-asking the server every time. And the location header carries the destination, which is the part Googlebot follows to learn the new canonical URL.

To produce that same response at the server level, the two most common configs are:

Nginx:

location = /old-blog/seo-tips {
    return 301 /blog/seo-tips-guide;
}

Apache (.htaccess):

Redirect 301 /old-blog/seo-tips /blog/seo-tips-guide

Both send the identical 301 status and Location header shown above. Server-level redirects are what Google recommends, since they are the fastest path and they apply before any application code runs.

Related Terms

• What is a 302 Redirect? covers the temporary counterpart and why Google keeps the source page in results for it.
• What is Link Equity? explains the ranking value that a permanent redirect carries to the new URL.
• What are Canonical Tags? shows the other main way to tell Google which URL is the authoritative one.
• What is a 404 Error? is what visitors and crawlers hit when a moved page has no redirect in place.
• What is HTTPS? covers the HTTP-to-HTTPS migration that always needs 301 redirects to avoid splitting signals.

Sources

• Redirects and Google Search, Google Search Central documentation (checked 2026-05-30)
• Site moves with URL changes, Google Search Central documentation (checked 2026-05-30)
• 301 Moved Permanently, MDN Web Docs (checked 2026-05-30)
• RFC 9110 HTTP Semantics, Section 15.4.2 (301 Moved Permanently) (checked 2026-05-30)