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4xx Client Error
What it means
A server sends 404 Not Found when no resource matches the requested URL, either because the path never existed or because its content was taken down.
| Property | Detail |
|---|---|
| Status class | 4xx Client Error |
| Defined in | RFC 9110, Section 15.5.5 |
| Cacheable by default | Yes. RFC 9110 lists it as heuristically cacheable, so a cache may reuse it without explicit freshness headers unless Cache-Control says otherwise. |
| Who needs to act | Whoever controls the link: the visitor for a typo, the site owner for a broken link or missing redirect. |
What does HTTP 404 Not Found mean?
HTTP 404 Not Found means the server has no current content at the requested URL, or will not reveal whether any exists. Typical causes are a mistyped address, a deleted or moved page, or a broken link. A 404 does not say whether the absence is temporary or permanent; 410 Gone is the code for a permanent removal.
How 404 Not Found works
A 404 is deliberately vague. RFC 9110 says it covers both 'not found' and 'not willing to disclose', and makes no claim about whether the absence is temporary or permanent. Because the code is heuristically cacheable, caches may keep serving a 404 after the page appears, unless the response sets a short Cache-Control lifetime. On a website the 404 page itself matters: it should keep the 404 status code while offering navigation, search and links to popular pages, so the visitor has somewhere to go instead of leaving.
Example 404 request and response
GET /blog/2019/old-announcement HTTP/1.1
Host: example.com
HTTP/1.1 404 Not Found
Content-Type: text/html; charset=utf-8
Cache-Control: max-age=300A short max-age stops browsers and CDNs caching the 404 for long, so a page published at this URL later is not hidden behind a stale error.
What causes a 404 Not Found
- A mistyped or truncated URL, often from a link copied by hand.
- A page that was deleted, or moved without a redirect.
- Broken internal links after a redesign or a change of URL slugs.
- Case-sensitive paths: /About and /about are different URLs on most Linux servers.
- API calls with the wrong version prefix or a resource ID that does not exist.
How to fix a 404 Not Found
If you are a visitor
- Check the URL for typos, missing characters or wrong capitalisation.
- Go up one level in the path, or use the site's search.
- Look the address up in a web archive if the page was removed.
If you run the site
- Add one-to-one 301 redirects from moved pages to their new URLs.
- Fix broken internal links, which a site crawler or Search Console's Page indexing report will list.
- Make the 404 template helpful but keep the 404 status; serving it with 200 creates soft 404s.
- Use 410 when you want to state that a removal is permanent.
404 and SEO
A 404 for a page that should not exist is normal. Google drops the URL from its index and gradually crawls it less often. The cases worth fixing are 404s on pages that still have value, such as moved content with inbound links that should have been redirected, and soft 404s, where a missing page returns 200 and Search Console flags it. Google documents that it handles 404 and 410 the same way, as it does every 4xx code except 429.
Related status codes
- 410 Gone: States that the removal is intentional and expected to be permanent.
- 403 Forbidden: The resource exists but access is refused; some servers answer 404 to hide that.
- 301 Moved Permanently: The fix when the content still exists at a new address.
Frequently asked questions
A server sends 404 Not Found when no resource matches the requested URL, either because the path never existed or because its content was taken down.
A mistyped URL, a deleted page, a broken link, or a route that was never implemented.
Double-check the URL for typos. Site owners: set up a proper 301 redirect if the page moved, or a helpful custom 404 page if it was removed.
Not in themselves. Google expects missing pages and simply removes them from the index. 404s matter when they hit pages that should exist, such as moved content with inbound links, or when a missing page returns 200 and becomes a soft 404.
Use 410 Gone if the page was removed on purpose and will not return, and 404 if you are unsure. Google treats both the same way, so the choice is mainly about telling other clients the truth.
Sources
Other 4xx Client Error codes
Reviewed by Raja Jahangir · Last reviewed: October 16, 2026