What Is a 404 Error?
A 404 error, or Not Found, is the HTTP status a server returns when a requested URL does not exist. Users see a 404 page, and crawlers register that the URL has no content. 404s commonly occur from deleted pages, mistyped URLs, or broken links pointing to nonexistent destinations.
A related issue is the soft 404, where a page returns a 200 OK status but shows little or no real content, confusing search engines about whether the page exists. Both should be identified and resolved.
How 404 Errors Affect SEO
A few 404s are normal and not inherently harmful; the web naturally has dead links. The problem arises at scale or on important pages. 404s on URLs that have backlinks waste that link equity, and 404s reached through internal links frustrate users and waste crawl budget.
Many 404s across a site can also signal poor maintenance. The priority is fixing 404s that have inbound links or traffic, since those represent lost authority and lost visitors, rather than chasing every minor dead URL.
How to Handle 404 Errors
For a 404 on a URL that has moved or has a relevant replacement, set a 301 redirect to the most appropriate live page to preserve link equity and guide users. For URLs with no replacement and no value, letting them return a proper 404 is correct, since not every dead page needs a redirect.
Monitor 404s in Search Console and with a broken link checker, prioritizing those with backlinks or internal links. A helpful custom 404 page that offers navigation and search also improves the experience when users do hit one.