What a 301 actually does
A 301 is an HTTP status code meaning moved permanently. A browser requesting the old URL is sent to the new one; a crawler is told the old address is retired and the new one replaces it.
Two consequences follow, and they are the reason redirects matter at all:
- People still arrive. Old links, old bookmarks and old citations keep working instead of hitting a dead end.
- Ranking signals transfer. The authority a page accumulated moves to its replacement.
That second point is why a botched redirect map costs traffic. The pages did not disappear — their history did.
Unlike a canonical tag, which is a hint, a redirect is a directive. The old URL stops serving content. There is nothing for a search engine to weigh up.
301, 302, 307, 410 — which one
Four codes cover almost every case, and choosing wrongly is a common and quiet error.
| Code | Means | Use when |
|---|---|---|
| 301 | Moved permanently | The change is permanent. The default choice |
| 302 | Found (temporary) | The original will genuinely return — A/B tests, short campaigns |
| 307 | Temporary redirect | Like 302 but preserves the request method. Rare in SEO |
| 410 | Gone | The content is deleted and has no replacement |
The 302 trap. A 302 tells search engines to keep the old URL indexed, because the move is temporary. Use one for a permanent move and you have asked Google to retain a URL that will never serve content again. Google often works out the intent eventually — but "eventually" can be months, and there is no reason to rely on it.
410 versus 404. Both mean the page is gone. A 410 says so deliberately, and tends to be dropped from the index faster. For content you removed on purpose, 410 is the honest answer.
Do not redirect everything to the homepage. When a page has no equivalent, redirecting it to the homepage is a soft 404 — the destination does not fulfil the original request. Google typically treats these as 404s anyway, and visitors who clicked expecting a specific article get a homepage and leave. If there is no relevant replacement, let it 404 or 410.
Redirect chains and loops
A chain is a redirect that points at another redirect: A → B → C. Every hop adds latency for the visitor, and crawlers limit how many hops they will follow before giving up.
Chains form naturally over years. A site moves to HTTPS, then drops www, then restructures its URLs, and each change adds a link to the chain without anyone removing the last one. Nobody makes a three-hop redirect deliberately.
The fix is mechanical: update every redirect to point at the final destination, so A → C and B → C. Then update your internal links to point at C directly, because an internal link to a redirected URL is a redirect you are inflicting on yourself on every visit.
A loop — A → B → A — makes the page unreachable for everyone. It is usually a misconfigured HTTPS or trailing-slash rule interacting with a CMS rule.
Where redirects leak value
Redirecting to an irrelevant page. Signal transfer depends on the destination being a genuine replacement. A product page redirected to a broad category may pass little, because the destination does not answer the original query.
Redirecting in bulk to one page. Two hundred retired articles pointed at one category page is a pattern Google treats as soft 404s. Map them individually or let them go.
Leaving internal links pointing at old URLs. The redirect works, but every internal link now costs an extra request, and you are telling crawlers your own site does not know where its pages live.
Redirecting a page that still ranks, without checking. Before retiring a URL, look at what it earns. Pages with steady organic traffic are frequently redirected during a tidy-up because nobody checked first. Capturing that baseline is the first step of any website migration, and the reason post-launch diagnosis is possible at all.
Chains that cross domains. Each hop has a cost, and cross-domain chains are the most likely to be abandoned by crawlers.
How to build a redirect map
For any restructure or move, the map is the work. Everything else is execution.
- Crawl the existing site and export every URL that returns 200.
- Pull the URLs that earn anything — organic clicks from Search Console, referral traffic from analytics, and pages with external links. A URL with no traffic and no links may not need a redirect at all.
- Match old to new, one to one, wherever a genuine equivalent exists.
- Decide explicitly for the rest. Closest relevant page, or 410. Not the homepage.
- Test before launch on staging, following each redirect to its final status.
- Re-crawl after launch and check for chains, loops and 404s that the map missed.
Step 2 is the one that gets skipped, and it is the one that turns a redirect map from a mechanical list into a prioritised one. If the map is large, the pages that earn are where accuracy matters.
After the move
Traffic dips after a restructure are normal — Google has to re-crawl, re-evaluate and re-index. What matters is the shape of the recovery.
Watch for three things:
- 404s in Search Console climbing. Each is a URL the map missed.
- Crawl stats, which should show the old URLs being fetched less over time as the redirects are absorbed.
- The pages you cared about, individually. An aggregate traffic line hides a specific page that lost its rankings.
If traffic has not begun recovering after several weeks, the cause is usually in the map — mismatched destinations, chains, or redirects that were never deployed at all.
Frequently asked questions
Does a 301 redirect pass full link equity?
Google has said it does not dampen PageRank through 301s. What still matters is relevance: a redirect to a genuinely equivalent page transfers signals well, while one to a loosely related page transfers less because the destination does not answer the original query.
How long should I keep a 301 in place?
At minimum a year, and indefinitely if the old URL still receives traffic or has external links. Removing a redirect turns every remaining old link into a 404.
301 or 302 for a site move?
- A 302 tells search engines the original will return and to keep it indexed, which is wrong for a permanent move and delays consolidation on the new URL.
Can I redirect old pages to the homepage?
You can, but it is usually counterproductive. A redirect to a page that does not fulfil the original request is treated as a soft 404, and visitors expecting specific content get a homepage. Redirect to the closest genuine equivalent, or return 410.
Moving a site without losing what it earns
Redirect maps are unglamorous and unforgiving. Most migration traffic losses are not mysterious algorithmic events — they are URLs that were never mapped, chains nobody cleaned up, or 302s that should have been 301s.
If you have a move coming and would rather not find out afterwards, the Safe SEO Site Migration covers mapping, testing and post-launch verification — $2,500, one-off, no retainer.