A 404 error is an HTTP status code that means the server cannot find the page at the URL a user has requested. It indicates that the page does not exist at that address, either because it was deleted, moved, or the URL was entered incorrectly.
What causes a 404 error?
The most common causes are: a page that has been deleted without a redirect in place, a URL that has been changed or restructured, a typo in a link on the site or an external site, a redirect that is pointing to a page that no longer exists, or a user mistyping a URL. During website migrations, 404 errors are common when old URLs are not mapped to their new equivalents with 301 redirects. Broken internal links can also create 404 errors by sending users to pages that have moved or been removed.
[Screenshot: Google Search Console Coverage report showing the Not Found (404) issue category with a count of affected URLs and an example list of pages returning 404 errors. Alt text: Google Search Console coverage report showing 404 not found errors with affected URL count and example URLs.]
How do 404 errors affect SEO?
A 404 error on a page that was never important and has no external links pointing to it is largely harmless. The problem arises when pages with backlinks or established rankings return 404. Any link equity pointing to a deleted or moved page is lost if no redirect is in place.
Google will also remove the URL from its index over time, losing any ranking position the page had accumulated. For websites undergoing migration or restructuring, managing 404 errors proactively is essential.
What is the difference between a soft 404 and a hard 404?
A hard 404 is a page that correctly returns a 404 HTTP status code when the URL does not exist. A soft 404 is a page that returns a 200 "OK" status code, indicating to search engines that the page exists, but displays a "page not found" message or thin, unhelpful content. Soft 404s are more problematic because Google may continue to crawl and index them, wasting crawl budget and potentially diluting site quality signals. Google Search Console flags soft 404s in the Coverage report.
How do I fix a 404 error?
If the page has moved to a new URL, implement a 301 redirect from the old URL to the new location. If the content has been permanently removed and there is no suitable destination to redirect to, confirm the page returns a genuine 404 or 410 status code rather than a soft 404. If the 404 is caused by a broken internal link, update the link to point to the correct URL. We use Google Search Console and site crawling tools to identify 404 errors during technical audits and resolve them as part of our standard SEO work.
Related KB articles:
• What is a 301 Redirect and When Should You Use One
• What is Technical SEO
• Google Search Console: A Quick Guide
External links:
• Google Search Central, HTTP status codes
Checking for and fixing broken links is part of routine website maintenance, and worth scheduling rather than leaving until rankings slip.