HTTP status codes explained: the complete guide in 3 minutes
200, 301, 404, 500: what each status code means, which ones matter for search, and what to do when your site returns the wrong one.
Every time a browser requests a page, the server answers with a number. You never see it when everything works, but that number decides whether Google keeps your page, replaces it or forgets it. Here are the only codes worth remembering.
The families
The first digit is enough to know what you are dealing with:
- 2xx: it worked
- 3xx: the page has moved
- 4xx: the request is at fault (often an address that does not exist)
- 5xx: the server crashed
200 — all good
The normal answer. The page exists and displays. Nothing to do.
301 — permanent move
The most important code for a small business redoing its website. It says: "this address has changed, here is the new one, permanently". Google then transfers the value the old page accumulated to the new one.
Without a 301, a redesign erases years of search visibility. Old addresses return an error, visitors arriving from an old link land nowhere, and rankings start from zero.
The redesign rule: every old address must point, through a 301 redirect, to the equivalent page on the new site. Not to the home page for everything — to the actual equivalent.
302 — temporary move
Tells Google: "keep the old address, I will be back". Useful during a few days of work. Used by mistake in place of a 301, it prevents the transfer of value. It is a frequent confusion, and a costly one.
404 — page not found
Normal in some cases: a discontinued product, an old promotion. It is not a fault in itself, and having 404s does not penalize a site.
What hurts is a 404 on a page that was getting visits or links. Two habits: check the 404s reported in Search Console, and 301-redirect the ones that mattered.
Also prepare a useful 404 page: a word of explanation, the search bar, the main links. Not a blank screen.
403 — forbidden
The file exists, but the server refuses to show it. Almost always a permissions problem or an overly broad security rule. If visitors report it, your host is who to call.
410 — gone for good
Like a 404, but deliberate and permanent. Google removes the page from its index faster. Useful for cleaning up after deleting hundreds of obsolete pages.
500 and 503 — the server has a problem
500: internal error. Often a WordPress plugin, a failed update, a broken script. The site is unreachable; this is the emergency.
503: service temporarily unavailable. This is the right code during planned maintenance: it tells Google to come back later without devaluing the pages.
How to check what your site returns
A browser extension that traces redirects shows the code of every page you visit. Search Console, for its part, lists the errors Google runs into across the whole site.
What to watch first: 404s on pages that had traffic, redirect chains (a page calling another, which calls a third), and any recurring 5xx.