What is a 301 Redirect and How Does It Work?
A 301 redirect permanently moves a URL to a new address. Here is how it works, when to use it, and how redirect chains affect SEO and crawl budget.
16 May 2026 · 7 min read
A 301 redirect is a permanent HTTP redirect from one URL to another. When a browser or search engine crawler requests a URL that returns a 301, it is automatically sent to a new destination URL. The original URL is no longer the active address for that content.
The "301" is the HTTP status code. It specifically means "Moved Permanently", telling browsers and crawlers that the move is not temporary.
HTTP/1.1 301 Moved Permanently
Location: https://www.example.com/new-page/
How do 301 redirects affect SEO?
When a URL is redirected with a 301, Google transfers most of the link equity (ranking power) from the old URL to the new destination. This is not instant: it takes time for Google to recrawl the old URL, follow the redirect, update its index, and consolidate the signals.
The amount of link equity passed through a 301 is very high but not 100%. Google has consistently said that "some" signal loss occurs. For practical purposes in most scenarios, treating a 301 as a full signal transfer is a reasonable working assumption.
More significantly, 301 redirects affect indexing: once Google has followed the redirect and indexed the destination, the original URL is dropped from the index. Searches will surface the destination URL, not the original.
When to use a 301 redirect
Changing a URL permanently
If you change the URL of a page (renaming a slug, restructuring a section), a 301 redirect is essential. Without it, users and crawlers who know the old URL get a 404. With it, they are sent seamlessly to the new location.
Migrating a site
Site migrations involve changing URLs at scale, sometimes for an entire domain. Every changed URL needs a 301 redirect from the old address to its equivalent new address. A migration without redirects is one of the fastest ways to lose organic traffic.
Consolidating duplicate content
If the same content is accessible at multiple URLs (with and without a trailing slash, HTTP and HTTPS, www and non-www), 301 redirects on the non-preferred versions enforce a single canonical URL and consolidate link equity.
Merging or deleting pages
When you delete a page or merge two pages into one, a 301 redirect from the deleted URL to the most relevant surviving page preserves any backlinks pointing to the old address.
Enforcing a preferred domain
Redirecting http:// to https://, or www.example.com to example.com (or vice versa), ensures Google indexes one consistent version of your site rather than treating both as separate entities.
301 vs other redirect types
| Status code | Name | Meaning | Link equity passed? |
|---|---|---|---|
| 301 | Moved Permanently | Permanent redirect | Yes |
| 302 | Found | Temporary redirect | Not reliably |
| 307 | Temporary Redirect | Temporary (preserves method) | Not reliably |
| 308 | Permanent Redirect | Permanent (preserves method) | Yes |
| 410 | Gone | Page permanently deleted | No |
The key distinction is 301 vs 302. A 302 redirect is temporary: it tells Google the original URL is still the preferred one and the redirect may be removed in future. Google typically does not consolidate link equity from a 302 redirect. If you intend the change to be permanent, always use a 301.
Redirect chains
A redirect chain is when URL A redirects to URL B, which redirects to URL C. Every hop in the chain adds latency, potentially reduces link equity transfer, and wastes crawl budget.
Redirect chains form when:
- A redirected URL is itself later redirected
- Internal links are not updated after a URL change
- Multiple migrations have accumulated without cleanup
The fix is to update all redirects to point directly to the final destination URL, bypassing intermediate hops. Crawly's crawl comparison and redirect reporting identify redirect chains across your site.
See how to find and fix redirect chains for the step-by-step process.
Redirect loops
A redirect loop occurs when two or more URLs redirect to each other in a cycle: A redirects to B, B redirects to A. The browser detects this and shows an error; crawlers abandon the loop after a set number of hops. Pages in a redirect loop cannot be indexed.
Redirect loops usually appear after misconfigured rewrite rules or CMS settings. A site crawler will flag them immediately.
How long do 301 redirects need to stay in place?
Technically, a 301 redirect should remain in place until all users and crawlers have updated to the new URL. In practice, this means keeping redirects in place indefinitely. Removing them after a year or two risks breaking bookmarks, external links, and cached references.
How to audit redirects on your site
Crawly crawls every URL on your site and reports:
- Which URLs return 301 responses
- What the final destination is after following the chain
- Any redirect chains (more than one hop)
- Any redirect loops
- Internal links that point to redirecting URLs rather than the final destination
After identifying redirect issues, update your internal links to point directly to the final URLs, and ensure your sitemap contains only the final, non-redirecting versions of each URL.
301 redirects are fundamental to maintaining SEO value when URLs change. Get them right and migrations and restructures are seamless. Get them wrong and you lose rankings, links, and traffic that took months to build.