Oops, you got an “HTTP 404 Not Found error”. That means the page you are looking for cannot be found (unless you were specifically looking for this page, then congratulations).

404 error explainer

Photo from johnhain CC0 Public Domain.

What is a 404 Error?

A 404 error is a status code that indicates the page you are looking for could not be found on a website’s server. Either the link you have is wrong, or the website didn’t use a 301 redirect to redirect an old URL to a new one.

A video from TED about the history 404 errors, not to be confused with 808’s (which are much cooler).

Sometimes people make clever 404 pages, or sometimes you’ll get a generic blank screen with code like:

  • “404 Error.”
  • “404 Not Found.”
  • “The requested URL [URL] was not found on this server.”
  • “HTTP 404 Not Found.”
  • “404 Page Not Found.”

FACT: A 404 error is one of the few mistakes that front end users see. It is, therefore, one of the most well-known errors on the web.

What Should I Do If I Get a 404 Error?

Don’t panic. Typically the content you are looking for wasn’t removed; rather a link was changed. You can use the site navigation or search bar to find the page. It’s polite to contact the site and let them know which URL is broken so they can also redirect the page.

What Other Error Codes are There?

404 errors are just one of many HTML error codes. Check out the list of common HTML error codes below.

List of Common HTML Error Codes From webmaster.iu.edu

 
Code Description Comment
100 Continue
101 Switching Protocols
200 OK Action completed successfully
201 Created Success following a POST command
202 Accepted The request has been accepted for processing, but the processing has not been completed.
203 Partial Information Response to a GET command, indicates that the returned meta information is from a private overlaid web.
204 No Content Server has received the request, but there is no information to send back.
205 Reset Content
206 Partial Content The requested file was partially sent.   Usually caused by stopping or refreshing a web page.
300 Multiple Choices
301 Moved Permanently Requested a directory instead of a specific file.   The web server added the filename index.html, index.htm, home.html, or home.htm to the URL.
302 Moved Temporarily
303 See Other
304 Not Modified The cached version of the requested file is the same as the file to be sent.
305 Use Proxy
400 Bad Request The request had bad syntax or was impossible to be satisfied.
401 Unauthorized User failed to provide a valid user name / password required for access to file / directory.
402 Payment Required
403 Forbidden The request does not specify the file name. Or the directory or the file does not have the permission that allows the pages to be viewed on the web.
404 Not Found The requested file was not found.
405 Method Not Allowed
406 Not Acceptable
407 Proxy Authentication Required
408 Request Time-Out
409 Conflict
410 Gone
411 Length Required
412 Precondition Failed
413 Request Entity Too Large
414 Request-URL Too Large
415 Unsupported Media Type
500 Server Error In most cases, this error is a result of a problem with the code or program you are calling rather than with the web server itself.
501 Not Implemented The server does not support the facility required.
502 Bad Gateway
503 Out of Resources The server cannot process the request due to a system overload.  This should be a temporary condition.
504 Gateway Time-Out The service did not respond within the time frame that the gateway was willing to wait.
505 HTTP Version not supported