404 Not Found HTTP Status Code


The HTTP status code 404 is one of the standard response codes in the Hypertext Transfer Protocol (HTTP), indicating that the server could not find the requested resource. When a web server receives a request from a client (like a web browser) for a resource that does not exist on that server, it responds with the status code 404.

Here are some key points about the 404 status code:

  1. Resource Not Found: The primary meaning of a 404 code is that the specific resource the request is looking for cannot be found on the server. This does not necessarily mean that the resource does not exist; it could have been removed, had its name changed, or be temporarily unavailable.

  2. User Perception: For users, encountering a 404 error can be frustrating because it indicates that they cannot access the page or resource they were trying to reach. Websites often customize their 404 error pages to provide a better user experience, offering suggestions for navigating back to the main site or searching for the missing content.

  3. No Indication of Cause: The 404 status does not provide any insight into why the resource is missing. It simply states the fact that the resource could not be found.

  4. SEO Impact: Frequent 404 errors can negatively impact a website's search engine optimization (SEO) if they signify broken or dead links. It's important for webmasters to regularly check for and fix such issues to maintain their site's SEO health.

  5. Customization: Many websites customize their 404 error page to make it more helpful or engaging for users. These custom pages might include links to popular or relevant content, a search box, or even creative and humorous elements designed to ease the disappointment of hitting a dead end.

  6. Server Response: While the 404 code is a client-side error indicating the client requested a resource that's unavailable, the server is responsible for delivering this code in response. This means the communication link between the client and server is working, but the specific requested resource is missing.

In essence, a 404 status code serves as a straightforward notification that the requested resource could not be found, prompting both users and webmasters to take further action, whether that's continuing to search for the desired content or addressing potential issues with the website's links or structure.


404 Not Found

Common Causes

Causes for a 404 error can include:

  1. Typing Error in URL: If the URL is mistyped in the address bar, the server will not find the intended resource. This is a common cause and can be as simple as a spelling mistake or a wrong character.

  2. Broken or Dead Links: Links that once led to a valid page but no longer do can result in a 404 error. This can happen if the target page is moved or deleted without updating the link accordingly.

  3. Moved or Deleted Resource: If a webpage or resource has been moved to a different location without proper redirection, or if it has been deleted from the server, accessing its original URL will result in a 404 error.

  4. URL Case Sensitivity: On some servers, URLs are case-sensitive. If the case of letters in the URL doesn’t exactly match that of the actual URL, it will result in a 404 error. For example, “Page.html” and “page.html” might be treated as different pages.

  5. Domain Name Not Resolving to the Correct IP: If the domain name does not properly resolve to the correct IP address due to DNS issues or changes, it can lead to a 404 error because the server with the requested resource cannot be found.

  6. Configuration Issues: Server configuration can also lead to 404 errors. If the server is not configured to handle the requested URL correctly, it might not serve the resource even if it exists.

  7. Crawling and Indexing Issues (for search engines): Sometimes search engines might display links to pages that have been recently removed or moved without proper redirection. Clicking on these links can lead to a 404 error.

To fix a 404 error, one can start by double-checking the URL for typos, refreshing the page, clearing the browser cache, or using a search engine to find the desired page if the direct link doesn't work. Webmasters can prevent broken links by regularly auditing their site for 404 errors and setting up proper redirections for moved or deleted content.

Browser Support

The following table will show you the current browser support for the 404 Not Found HTTP status code.

Edge Chrome Firefox Opera Safari
Tablets / Mobile
Chrome Firefox Opera Safari Samsung Webview

Last updated by CSSPortal on: 1st April 2024