A custom 404 page is the page a server shows when a requested URL does not exist, designed to help visitors continue. For SEO, the HTTP status code matters as much as the design: the page must return 404 (or 410).
What does it mean for SEO?
Google’s Search Console help states that 404 errors on non-existent URLs do not harm a site’s search performance. Pages that do not exist should return a real 404 status, and Google treats 410 like 404. Google lists redirecting such URLs to the homepage and blocking them in robots.txt among practices that create soft 404 errors. A soft 404 is a page that returns 200 but shows an error message, which Search Console reports as such.
RFC 9110 defines 404 as the server being unable to find the target resource and makes the response cacheable by default.
On design, according to reports, a clear message, a search box and links to popular sections help visitors. Google does not require them.
| Response | Status code | Meaning per RFC 9110 | What Google does | When to use it |
|---|---|---|---|---|
| Not Found | 404 | no current representation found; doesn't say whether this is temporary or permanent | doesn't use the content, removes a previously indexed URL and gradually crawls it less often; newly found 404 URLs aren't processed | Page removed with no replacement |
| Gone | 410 | no longer available, likely permanently | same as 404 | same as 404; per the RFC preferred when the removal is known to be permanent |
| Soft 404 (error message or empty page) | 200 | request succeeded | detects an error page from its content, excludes it from Search and reports a soft 404 in the Page indexing report | avoid; depending on the case, return 404/410, redirect to the replacement or fix the loading problems |
| Redirect to replacement | 301 | moved permanently | follows the redirect; a strong signal that the target should be processed | Content has moved or has a clear replacement |
| Page with content | 200 | request succeeded | passes the content on to indexing; inclusion isn't guaranteed | Page exists and shows real content |
A designed error page with search and links is useful according to Google, as long as the server still returns 404 or 410. 4xx codes other than 429 don't change the site's crawl rate. Google can also flag good pages as soft 404 if they render empty or broken for Googlebot, for example because resources are blocked by robots.txt. Sources: Google Crawling Infrastructure: How HTTP status codes affect Google's crawlers (last updated 2026-02-04); Google Search Central: Troubleshoot Google Search crawling errors, soft 404 errors (last updated 2025-12-18); RFC 9110: HTTP Semantics, 15.3.1 200 OK, 15.4.2 301, 15.5.5 404, 15.5.11 410. Last checked: .
Finding 404 hits in web analytics
A searchVIU guide (2018, updated 2026) explains how to find 404 hits in Google Analytics 4. The error page has to load on the requested URL, include the tracking code and use a distinctive page title. Filtering by page title and referrer then separates broken internal links from external ones. GA4 filters out known bots automatically, so errors that only crawlers run into show up in Search Console instead.
Example
HTTP/1.1 404 Not Found
Content-Type: text/html
<h1>This page does not exist</h1>
<p>Go to the <a href="/">homepage</a> or search the site.</p>
Common mistakes
- The error page returns status 200 (soft 404).
- All missing URLs redirect to the homepage.
- The 404 page is blocked in robots.txt.
More on the searchVIU blog
Sources
- Fix 404 errors – Search Console Helpsupport.google.com
- RFC 9110, section 15.5.5 404 Not Found – IETFrfc-editor.org
- HTTP status codes, network and DNS errors – Google Search Centraldevelopers.google.com
- Monitor & Fix 404 Errors with Google Analytics 4 – searchVIU blog (2018, updated 2026)searchviu.com
- [GA4] Known bot-traffic exclusion – Analytics Helpsupport.google.com
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