301 redirects and 404 pages: what they are and when to use them

A 301 redirect is a server instruction saying: «this page has moved permanently to a new address», which automatically takes people and Google to the new page and passes on the old page’s signals. A 404 page instead says: «this page doesn’t exist». Use a 301 when a page has a successor (a new address, a similar product), a 404 or 410 when it doesn’t.

Websites change: new products, renamed addresses, deleted pages. Each time, someone can still arrive at the old address: from a link on another site, a bookmark, Google. What they find depends on how you handled the change.

The 404 page

404 is an HTTP status code: the message the server uses to say “this page isn’t here”. A good 404 page still helps the person: it explains what happened and offers useful links (categories, search, homepage). 404 pages don’t penalise a site: it’s normal for old pages to disappear.

404, 410 and soft 404

Case	Code	What Google understands
404 Not Found	404	The page isn’t there; if it stays that way, it drops out of the index
410 Gone	410	The page was removed on purpose; it drops out a little faster
Soft 404	200	The server says “all fine” but the page is empty or says “not found”: an error to fix

A soft 404 happens, for example, when a shop shows “Product unavailable” on an empty page with a 200 code, or when every removed page is sent to the homepage: Google treats them as not found and flags them in Search Console.

The 301 redirect

A redirect automatically sends the person (and Google) from one address to another. 301 means “moved permanently”: Google understands the new page replaces the old one and passes its signals on.

301, 302, 307 and 308: the difference

Code	Meaning	When to use it
301	Moved permanently	Final change of address: the most used
308	Permanent, like 301, keeping the request method	Forms and APIs; for normal pages it’s equivalent to 301
302	Moved temporarily	A page replaced for a few days (e.g. a promotion)
307	Temporary, like 302, keeping the method	Technical cases; for normal pages it’s equivalent to 302

For Google, permanent redirects are a strong signal that the new address becomes the canonical one; temporary ones are a weak signal. If a 302 stays in place for a long time, Google may treat it as permanent anyway.

When to use what

Situation	What to do
The page has changed address	301 to the new address
The product is replaced by a similar one	301 to the new product
The product no longer exists and has no replacement	301 to the category, or 404
The page never existed (a typo)	404

How to set up a 301 redirect

It depends on where the site is hosted:

• Apache server: in the .htaccess file, a line like Redirect 301 /old-page/ https://www.example.com/new-page/.
• Nginx server: in the configuration file, with the return 301 instruction.
• WordPress: with a redirect plugin, without touching code.
• Static hosting (Cloudflare, Netlify): in a _redirects file, one line per rule: /old-page/ /new-page/ 301.

This site, Peacchy, uses exactly that _redirects file on Cloudflare.

Redirect chains

When a site changes structure several times, redirects pile up: /product.php?id=12 leads to /green-teas/sencha/, which leads to /green-teas/organic-sencha/. Each hop slows the page and loses some signals. Googlebot follows up to 10 redirects in a row, then stops and reports an error. The fix is to point the first address directly to the last, and update internal links so they point straight to the final address.

How long to keep a redirect

Google recommends keeping redirects as long as possible, generally at least a year: that’s the time Google needs to transfer signals and for old external links to keep working. If other sites link to the old address, keep them forever.

How to find problems

• In Search Console, the Pages report lists “Not found (404)” pages.
• A crawler (a program that visits the whole site like Google) lists broken internal links and redirect chains.

Checklist when you change your site’s URLs

1. List all old addresses (from the sitemap, Search Console, a crawler).
2. Match each old address to the most similar new one.
3. Set up the 301s and test them one by one.
4. Update internal links, menus and the sitemap.
5. In the following days, check the Pages report in Search Console.

Peacchy’s SEO Simulation has you do both: you find a 404 page with links from other sites and a redirect chain, and fix them from the shop’s admin panel.

Google’s other instructions (noindex, robots.txt, canonical) are explained in noindex, robots.txt and canonical: the differences.

Sources

• Redirects and Google Search (Google Search Central)
• Site moves with URL changes (Google Search Central)
• How HTTP status codes affect Google Search (Google Search Central)