What Is a 404?
A 404 error is an HTTP status code sent by a web server to a browser that signals the requested web page or resource cannot be found. This condition may be temporary or permanent.
The most common reasons a 404 error occurs include:
- The web page does not exist.
- The URL is a dead or broken link.
- The content has been moved without a 301 redirect put into place.
- The user makes a mistake when typing in the URL into a web browser.
- Another website links to an incorrect URL.
In regards to search engine optimization (SEO), 404 Not Found errors typically do not impact a website’s search engine performance if the URL causing the error should not exist on your site. Those types of 404 errors can be safely ignored.
However, if the URL did exist on the domain at some point in time, and the web page has backlinks pointing to it, then a 404 error can affect a website’s search engine visibility. Without a proper 301 redirect put into place to a new URL, the PageRank value of the incoming links will be lost; meaning the website would be losing a potential increase in Page Authority and Domain Authority from the transfer of PageRank (or link equity).
Visit the SEO Glossary
Go to the SEO Glossary to find more terms and definitions that relate to the field of search engine optimization.