A 301 redirect permanently sends users and search engines from one URL to another, passing the old page’s ranking signals to the new one. It is the correct way to move or retire a page without losing the traffic it earned. Get it wrong — the wrong status code, a chain of hops, a loop — and you leak rankings that took years to build.
Redirects are the plumbing of technical SEO. Nobody notices them until they break, and when they break during a migration they can erase months of organic traffic overnight. This guide covers what a 301 actually does in 2026, which status code to use when, the mistakes I find on almost every audit, and a redirect mapping framework you can run yourself.
What a 301 Redirect Actually Does
A 301 is an HTTP status code that means “moved permanently.” When a browser or crawler requests the old URL, the server responds with a 301 and the location of the new URL, and the request is forwarded there automatically. The user sees the new page; the search engine learns the old URL is retired.
For SEO, three things happen. The new URL inherits the ranking signals — links, relevance, historical authority — associated with the old one. The old URL drops out of the index over time as Google reprocesses it. And any internal or external links pointing at the old URL still resolve, so you do not bleed referral traffic or link equity into a 404.
The single most important shift to understand is that 301s no longer cost you PageRank. For years the accepted wisdom, popularised by Moz’s guidance on redirection, was that a 301 passed roughly 90-99% of link equity — a small tax on every redirect. Then in 2016 Google’s Gary Illyes stated publicly that 3xx redirects no longer lose any PageRank at all. That is still the position in 2026. A clean 301 passes full value.
301 vs 302 vs 307: Which Status Code and When
Choosing the wrong status code is the most common redirect mistake I see, and it is entirely avoidable once you know the rules. The status code is a signal about permanence, and Google treats each one differently.
301 — Moved Permanently. Use this for anything permanent: a changed URL, a consolidated page, a retired product moved to a category, a domain migration. This is the default for SEO. It tells Google to transfer signals and swap the indexed URL.
302 — Found (temporary). Use this only when the move is genuinely short-term. A/B testing a new template, a seasonal offer page, geo-redirecting a user for a session. A 302 tells Google to keep the original URL indexed. Ship a 302 where you meant a 301 and Google may keep ranking the old, now-empty URL for weeks.
307 — Temporary Redirect. The HTTP/1.1 strict version of a 302, most often seen with HSTS forcing HTTPS. From an SEO standpoint Google treats a 307 like a 302 — temporary. You rarely set these deliberately.
308 — Permanent Redirect. The strict permanent equivalent of a 301. Functionally SEO-equivalent to a 301 in Google’s eyes. Most servers and CMS platforms still default to 301, and there is no ranking reason to switch.
The practical rule: if the change is permanent, use a 301 (or 308). If it is not permanent, ask whether you should be redirecting at all. Misusing HTTP status codes is one of the technical issues I flag most often on a technical SEO audit, because a single mislabelled redirect on a high-authority URL can quietly stall an entire section of a site.
Where 301 Redirects Go Wrong
Redirects fail in predictable ways. In my experience auditing sites across more than 200 projects, the same four problems account for the overwhelming majority of redirect-related traffic loss.
Redirect chains. URL A redirects to B, which redirects to C, which finally lands on D. Each hop is an extra request, extra latency for users, and extra crawl cost. Google Search Central’s documentation on redirects states that Googlebot follows up to 10 hops in a single chain before giving up — but you should never get close to that. Every hop delays how quickly the final URL consolidates signals. Chains accumulate silently over years of site changes, which is why an audit almost always surfaces them.
Redirect loops. A redirects to B, and B redirects back to A. The page never resolves, users get an error, and the content is effectively deindexed. Loops are usually caused by conflicting rules — a trailing-slash rule fighting an HTTPS rule, for instance — and they are urgent because the affected pages return nothing at all.
Redirecting everything to the homepage. When a site retires hundreds of URLs, the lazy fix is to point them all at the homepage. Google treats a redirect to an irrelevant page as a soft 404 and often ignores the signal transfer entirely. Redirect each old URL to its closest live equivalent, or let it 404 honestly if no equivalent exists.
Internal links still pointing at redirected URLs. Even a perfect 301 is wasteful if your own navigation, sitemaps, and internal links keep pointing at the old URL. Every internal link should be updated to hit the final destination directly, so neither users nor crawlers pay the redirect tax on every visit.
The Redirect Mapping Framework
When you change URLs at scale — a redesign, a platform switch, a domain move — a redirect map is the artefact that makes or breaks the outcome. This is the five-step process I use on every migration.
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Crawl the current site fully. Use Screaming Frog or Sitebulb to export every indexable URL, plus its status code, canonical, and internal link count. Pull the same list from Google Search Console and your XML sitemaps. The goal is one complete inventory of every URL Google currently knows about.
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Layer in performance and link data. Export organic landing pages from GSC (last 12 months) and your top backlink targets from Ahrefs’ guide to 301 redirects or Semrush. Now every URL in your inventory carries its traffic and authority weight, so you know which redirects actually matter.
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Map old to new, one to one. For each old URL, assign the single most relevant new URL. Not the homepage, not a generic category — the closest content match. Where no equivalent exists, mark it to 404 or 410 deliberately rather than forcing a bad redirect.
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Flatten every chain. If an old URL already redirects somewhere that will itself move, point the old URL straight at the final destination. The map should contain zero chains before it ships.
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Implement, then verify in staging. Deploy the redirects and re-crawl staging to confirm every old URL returns a single 301 to a live 200 URL. Fix any 302s, chains, or loops before going live — not after.
Keep the map as a living spreadsheet. After launch it becomes your monitoring baseline: any old URL that stops returning a clean 301 is a regression you can catch immediately. Structured redirect mapping is the difference between a migration that holds its rankings and one that spends three months recovering.
301 Redirects in Site Migrations
Migrations are where redirects earn their reputation. The pattern is depressingly consistent: a company relaunches, forgets a section of legacy URLs, and watches a third of its organic traffic vanish. The redirects were the safeguard, and they were incomplete.
The rule for migrations is total coverage. Every URL that had value on the old site needs a 301 to its equivalent on the new one — including URLs that only rank for long-tail queries, because in aggregate they carry real traffic. Partial redirect maps are the leading cause of migration traffic loss, and I cover the full sequence in the site migration guide.
Keep old redirects live for at least a year, ideally permanently. Google needs repeated crawls of the old URL to fully transfer signals and swap the indexed version, and external sites will keep linking to old URLs long after you have forgotten them. Removing redirects too early re-breaks links you already fixed. If you are unsure how long to hold them, the answer is longer than you think — storage is cheap, re-earning lost authority is not.
Redirects and Crawl Budget
On small sites, redirects have a negligible crawl cost. On large sites — ecommerce catalogues, publishers, marketplaces with hundreds of thousands of URLs — they become a real bottleneck. Every redirect Googlebot fetches is a crawl request that returns no indexable content.
When thousands of redirects sit in your internal link graph, or chains multiply the number of requests per destination, Googlebot spends its allocation shuttling between old URLs instead of discovering and refreshing live pages. This is why redirect cleanup is a core part of any crawl budget optimisation project. The fix is the same one from the mapping framework: no chains, no loops, and no internal links pointing at redirected URLs.
How to Test and Monitor Your Redirects
Redirects are not a set-and-forget task. CMS updates, plugin conflicts, and new rules regularly reintroduce chains and loops. Build a lightweight monitoring habit.
Run a full crawl monthly and filter for any URL returning a 3xx that is still linked internally, any chain longer than one hop, and any 302 on a permanent URL. Check the Google Search Console Page Indexing report for “Page with redirect” entries that should not be there. For spot checks, browser extensions like Redirect Path or a quick curl -I on the command line show you the exact status code and hop sequence for any single URL.
The goal is boring: every legacy URL returns exactly one 301 to a live page, and nothing internal links through a redirect. When you can prove that, your 301 redirects are doing their job — preserving the rankings you earned while the URLs beneath them change. If you want a second set of eyes on a migration before it ships, that verification is exactly the kind of work a technical SEO consultant should be doing with you.
Frequently Asked Questions
Are 301 redirects permanent, and can I undo one? A 301 signals permanence to search engines, but the redirect itself is just a server rule you control — you can remove or change it at any time. That said, once Google has swapped the indexed URL, reversing a 301 means Google has to re-process everything again, which takes time and can cause temporary ranking wobble. Treat 301s as permanent decisions even though they are technically reversible.
Will a 301 redirect pass my backlinks to the new page? Yes. The links pointing at the old URL continue to pass their authority through the 301 to the destination. This is exactly why redirecting a retired page is far better than deleting it — you keep the accumulated link equity instead of throwing it into a 404.
How long does it take Google to process a 301 redirect? It varies with how often Google crawls the URL. High-authority pages that Google visits frequently can swap in days; low-traffic pages buried deep in a site can take weeks or months. Keeping the redirect live and linking to the new URL internally speeds up the process.
Should I redirect HTTP to HTTPS with a 301? Yes. A site-wide 301 from HTTP to HTTPS is standard practice and the correct way to consolidate signals on the secure version. Make sure the redirect goes straight to the HTTPS version of the same URL, not through the homepage, and that it does not create a chain with your www/non-www rule.
Do 301 redirects help or hurt page speed? Each redirect adds a round-trip before the real page loads, so a chain of redirects measurably hurts load time and Core Web Vitals. A single 301 has a small, usually acceptable cost. The performance argument is another reason to flatten chains and update internal links to point directly at final URLs.
