What Is a 404 Page? | SEO Glossary

A 404 page is the HTTP status code (404 Not Found) returned by a server when the requested URL does not exist. When a browser or search engine crawler attempts to access a specific URL and the server cannot locate the corresponding page, it responds with a 404 status and informs the visitor that the page is unavailable.

Why It Matters

A 404 error interrupts the visitor's browsing flow and can diminish trust in a website. Google's John Mueller has stated that 404 responses do not directly harm a site's overall search rankings. However, the individual page returning a 404 will be removed from the search engine's index. If external sites link to a URL that returns a 404, the link equity those backlinks carry is lost, potentially weakening the site's overall authority. An excessive number of 404 errors can also signal poor site maintenance to search engines, so regular monitoring and management are essential.

Common Causes of 404 Errors

Page deletion or URL changes: Content is removed or the URL structure is updated without setting up a redirect to the new location.
Mistyped URLs: Visitors manually enter an incorrect address, or an external site links to a misspelled URL.
Broken internal links: Links within the site point to pages that no longer exist, creating broken link paths.
Server configuration issues: During server migrations or domain changes, existing URL paths are not correctly mapped to their new locations.
Outdated external links: Other websites link to URLs that have since changed, but those external sites have not updated their links.

SEO Impact

A 404 error is a standard HTTP response that tells search engines a URL does not exist. Google has explicitly stated that 404 errors do not affect the rankings of other pages on the same site. However, indirect effects do exist. First, when a page with backlinks returns a 404, the link equity from those backlinks is lost. Second, crawlers repeatedly visiting 404 pages can waste crawl budget that would otherwise be spent on indexable content. Third, visitors who land on 404 pages are more likely to bounce, which can negatively affect overall user experience metrics. It is important to note that redirecting all 404 pages to the homepage or blocking them via robots.txt is discouraged by Google, as both approaches hinder its ability to understand the site's structure.

Designing an Effective Custom 404 Page

Creating a custom 404 page instead of relying on the default server error screen can significantly improve user experience. An effective custom 404 page should include several key elements. It should clearly communicate that the requested page was not found. Maintaining the site's global navigation allows visitors to easily move to other sections. Providing a search function lets visitors find the content they were looking for. Displaying popular posts or recommended content links helps reduce bounce rates. Critically, the custom 404 page must return a proper HTTP 404 status code rather than a 200 status code, which would create a soft 404 that confuses search engines.

404 vs 410 Differences

A 404 (Not Found) indicates that the page cannot currently be found, while a 410 (Gone) explicitly states that the page has been permanently removed. Search engines will recrawl a 404 URL after some time, but they treat a 410 URL as permanently deleted and remove it from the index more quickly. According to an experiment by Reboot Online, URLs returning a 410 status code were de-indexed approximately three times faster than those returning a 404 (an average of 4 days versus 12 days). When content has been intentionally removed and no replacement page exists, using a 410 is more efficient for crawl budget management. That said, Google's John Mueller has noted that the processing of 404 and 410 is practically very similar, meaning a 404 is sufficient in most cases.

How inblog Helps

inblog automatically removes deleted posts from the sitemap and provides redirect management to reroute 404s to replacement URLs.

404 Page