Understanding 404 Errors On The Web 101

Have you ever encountered a 404 page while out browsing the web? I reached out to colleague Matthew Edgar here in Denver who helps people find and correct 404 errors on their sites. He has prepared the following short tutorial about 404 errors.

If you are like most people, you have, at least on occasion. You click on a link—maybe in a Google search result or maybe a link a friend shared on Facebook—and instead of the page you were hoping to see, you get an error message telling you that page could not be found. What exactly is that 404 error message and why are you seeing it instead of the page you wanted?

What Exactly Is That 404 Error Message?


To understand a 404 error it helps to think of the web as a collection of addresses, with addresses represented by URLs. A URL is a specific address for a particular file somewhere on the web. That file might be a page, an image, or a video. Encountering a 404 error means that a website doesn’t have any file located at that URL.

When the website couldn’t find a file to associate with that URL, the website instead returned an error message indicating nothing was found. The numbers “4-0-4” comes are the numerical signal the website sends to indicate nothing was found.

Why Are You Seeing The 404 Error?

While you can arrive at the 404 error page on a site for any number of reasons, there are two common reasons why you will typically encounter that 404 not found error page:

1. The URL may be typed incorrectly. Maybe a friend copied and pasted the URL wrong before sharing the link. Maybe a blog encoded a link in their text incorrectly and, as a result, sent their readers to a 404 error page. Or, maybe you typed in the URL yourself and left off a letter.

2. Another reason people find 404 errors is because the website you are looking at recently removed pages from their site or moved those pages to a new URL. Other websites, social networks, and search engines, might not know about that change and are still sending you, and others, to the old URL.

What Does This Mean For My Site?

If you run a website, you are probably wondering what this means for you. Because visitors can encounter 404 errors on any site, some of your visitors are probably encountering 404 errors on your site. The more visitors you have and the more pages you have, the better the chances of your visitors encountering 404 errors on your site.

The real problem with 404 errors is that those errors can cause you to lose visitors. Around 65% of people who reach a 404 error page leave that website altogether. If just 3 people encounter a 404 error on your site each day, you could be losing about 60 visitors every month due to your site’s 404 not found error pages.

Ultimately, the only way to know how 404 errors affect people visiting your website is to monitor what 404 errors your visitors encounter. If you know how people reached that 404 page—from a search result, another website, a social network, or somewhere else on the web—you can correct those 404s to keep your website clean and error-free.

Matthew Edgar is the founder of 404 Manager and Monitor SpringTrax, which helps web managers find and fix every 404 error that visitors encounter on their site.

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