What is a 301 Redirect?

A 301 redirect is a permanent redirect that sends both visitors and search engines from one URL to another. The number 301 refers to the HTTP status code that gets sent behind the scenes when someone requests the old URL. It tells browsers and search engines that the page has moved permanently to a new location, and that they should update their records accordingly.

Why It Matters for SEO

When a page accumulates backlinks, rankings, and authority over time, that value is tied to its URL. If you delete that page or change its URL without setting up a redirect, all of that accumulated value disappears. The old URL returns a 404 error, links pointing to it become worthless, and any rankings it held are lost.

A 301 redirect preserves that value. Google transfers the majority of the link equity from the old URL to the new one, meaning the page can continue ranking under its new address without starting from scratch. This is why redirects are considered one of the more consequential technical SEO decisions you can make on a site, and why getting them wrong has real consequences for your off-page SEO efforts that took months to build.

When You Actually Need One

The most common situations where a 301 redirect is necessary include changing a page's URL slug, moving your site to a new domain, consolidating two similar pages into one, or switching from HTTP to HTTPS. Any time a URL that has existing traffic or backlinks pointing to it needs to change, a 301 redirect should be part of that process without exception.

It also comes up frequently when fixing duplicate content issues, where multiple URLs serve the same content and need to be consolidated into a single preferred version.

What a 301 is Not

A 301 redirect is permanent, which distinguishes it from a 302 redirect, which signals a temporary move. Using a 302 when you intend a permanent change is a common mistake that prevents Google from fully transferring link equity to the new URL. If you are moving a page and have no intention of bringing the old URL back, a 301 is always the right choice.

Redirects are one of those technical details that feel minor until something goes wrong. A site migration handled without proper redirects in place is one of the fastest ways to lose rankings that took months to earn, which is exactly the kind of issue covered in SEO fixes that end up hurting rankings.