What is a 404 error?

A 404 error is an HTTP status code that indicates that the server has received the user's request but cannot find the requested page or resource. In other words, the URL does not exist (anymore) or has been entered incorrectly. For the visitor, this usually appears as a “Page Not Found” message.

Causes of a 404 Error

A 404 can occur for various reasons:

• The page has been removed without a redirect.
• The URL was misspelled or entered.
• There is an error in internal or external links.
• The website has moved but without proper redirects.

Not every 404 is harmful. Sometimes it is logical that a page no longer exists, for example with old promotions or expired products.

Impact of 404 errors on SEO

An occasional 404 isn't immediately bad for your rankings, but many 404s can cause problems:

• Poor user experience: visitors drop out more quickly if they repeatedly encounter dead links.
• Loss of link value: backlinks to a 404 page no longer carry SEO value.
• Crawl budget waste: Search engines spend time on pages that deliver nothing.

That is why it is important to take a critical look at which 404s are acceptable and which are better solved with a 301 redirect.

How do you deal with 404 errors?

As an SEO specialist, I recommend that you always monitor and review 404s.

• Use redirects where appropriate: if a page has moved permanently, set up a 301 redirect to the new or most relevant page.
• Let some 404s exist: if content is really no longer relevant and there is no alternative, a 404 may remain. Or refer it to the home page.
• Check regularly in Google Search Console: Here you can see which URLs return a 404.

A good balance is important: not every 404 needs to be fixed, but dead links with valuable backlinks or high traffic numbers do.

Custom 404 pages

A standard 404 message is often bare and unclear. By a custom 404 page by making you improve the experience of visitors. Here, for example, you can:

• Provide a search function.
• Suggest popular or relevant pages.
• Show a friendly message in your own branding.

This way, you prevent visitors from dropping out immediately and you offer them a chance to continue on your website.

Conclusion

A 404 error simply means that a page does not exist or cannot be found. For SEO, it's important to be smart with 404s: use 301 redirects for important content, but feel free to let irrelevant pages return a 404. Combine this with a user-friendly custom 404 page and you'll limit the negative effect for both search engines and visitors.