A 404 error is one of the most common website errors. You may see it when you click a link or open a URL that no longer works.
So, what is a 404 error?
A 404 is an HTTP status code. It means the web server cannot find the requested page or resource. It often appears as 404 Not Found.
A 404 does not mean the whole website is down. Usually, only one URL or page is missing.
For website owners, finding unwanted 404s is an important part of website maintenance and technical SEO.
What Does 404 Not Found Mean?
When you open a web page, your browser sends a request to the website’s server.
The server looks for that page. If the resource is missing, the server response may return a 404 status code.
You may see an error message such as:
- 404 Not Found
- Page Not Found
- This page does not exist
- The requested page is unavailable
The wording depends on the website.
A 404 error page simply tells visitors that the requested resource could not be found at that URL.
What Causes a 404 Error?
A 404 can appear for several reasons.
1. Deleted Page
A deleted page can still appear in old links, bookmarks, or search engine results.
For example, you may delete an old blog post, but other pages may still link to it.
Visitors who follow those links will reach a missing page.
2. Incorrect URL
A typing mistake can create a broken URL.
For example, the correct URL might be:
example.com/seo-guide/
But someone enters:
example.com/seo-guid/
If that address does not exist, the server may return a 404.
3. Changed URL
Website owners sometimes change URLs.
If /old-guide/ becomes /new-guide/ without a URL redirect, the old address may stop working.
4. Broken Links
Broken links can point visitors to pages that no longer exist.
This often happens when content is removed but links from other pages on your site are not updated.
5. Website Migration
Moving a site or changing its URL structure can create crawl errors if redirects are not set correctly.
How to Fix a 404 Error
The right solution depends on why the error occurs.
Check the URL
First, check the address for spelling mistakes or missing characters.
A simple typo may be the entire problem.
Fix Broken Links
Update internal links that point to missing or incorrect URLs.
Visitors should reach the correct page directly.
Restore the Page
If useful content was deleted by accident, restore it at its original URL when possible.
Use a 301 Redirect
A 301 redirect is useful when a page has permanently moved.
For example:
/old-guide/ → /new-guide/
This sends users and search engines to the new location.
Do not redirect every missing page to your homepage. Use a 301 only when there is a relevant replacement.
Keep the 404 When Needed
Not every 404 needs fixing.
If content was intentionally removed and has no suitable replacement, a proper 404 response can be correct.
404 vs 301 Redirect
A 404 and a 301 serve different purposes.
404 Not Found: The requested page cannot be found.
301 Redirect: The page has permanently moved to another URL.
If an article moves to a new address, use a 301.
If the content has been permanently removed and no relevant replacement exists, a 404 may be suitable.
404 vs 403 Forbidden
A 404 normally does not mean you were blocked.
A 403 Forbidden response is different.
404: Resource not found.
403: Access to the resource is denied.
These are separate HTTP status codes with different meanings.
Other Common Website Errors
A 404 is not the only error you may see.
A 500 Internal Server Error means the server encountered a problem while handling the request.
A 502 Bad Gateway can occur when one server receives an invalid response from another server.
A 503 Service Unavailable means the server is temporarily unable to handle the request. This can happen during maintenance or heavy traffic.
Do 404 Errors Affect SEO?
Some 404 pages are normal and do not automatically hurt search engine rankings.
Problems can happen when important pages disappear by mistake or many internal links point to missing URLs.
For example, an article may receive organic traffic and have many internal links. If it is accidentally deleted, visitors and crawlers may repeatedly reach a 404.
This creates a poor user experience.
Search engines may also discover missing URLs after they have crawled your site.
Good technical SEO therefore involves checking important errors and fixing those caused by mistakes.
How to Find 404 Errors
Website owners have several ways to find missing URLs.
Google Search Console
Google Search Console can help you identify URLs that Google tried to crawl but could not find.
When you discover one, ask:
- Should this page exist?
- Is another page linking to it?
- Is there a suitable replacement?
- Was it intentionally deleted?
The answer will help you choose the right action.
Website Crawlers
SEO crawling tools can scan your website for broken links, redirects, status codes, and other problems.
This is useful for large websites.
Check XML Sitemaps
Your XML sitemaps should contain valid URLs that you want search engines to discover.
Remove old or deleted URLs when appropriate.
What Is a Custom 404 Page?
A custom 404 page gives visitors useful options when a page cannot be found.
Instead of showing only a basic error, it can include:
- Homepage link
- Search box
- Main navigation
- Popular pages
- Useful categories
- Related content
This makes it easier for visitors to continue browsing.
A custom design should still return the correct 404 HTTP status when the requested resource does not exist.
404 Errors in Content Management Systems
Popular content management systems make it easy to change page URLs.
However, changing a URL without updating links can cause errors.
For example, changing a WordPress post slug may leave old links pointing to the previous URL.
After changing an important URL:
- Check the old address.
- Update internal links.
- Add a 301 when appropriate.
- Update your XML sitemap.
- Test the new page.
These simple steps can prevent many unnecessary 404s.
Common 404 Mistakes
One mistake is redirecting every missing page to the homepage.
Another is ignoring broken internal links.
Website owners should also avoid keeping deleted URLs in menus and sitemaps.
A better approach is to restore pages that should exist, fix broken links, redirect moved content, and keep legitimate 404 responses when no replacement exists.
Frequently Asked Questions
What Is a 404 Error?
A 404 error is an HTTP status code that means the server could not find the requested page or resource.
How Do I Fix a 404 Error?
Check the URL first. Then fix broken links, restore accidentally deleted content, or use a relevant 301 redirect when the page has moved.
Is a 404 Error Bad for SEO?
Not always. Normal 404 pages are part of the web. Unexpected errors on important pages and large numbers of broken links should be investigated.
Does a 404 Mean I Was Blocked?
Usually, no. A 404 means the resource was not found. A 403 Forbidden response is more commonly related to denied access.
What Is the Difference Between 404 and 500?
A 404 means a resource cannot be found. A 500 Internal Server Error means the server encountered a problem while processing the request.
Final Thoughts
A 404 error means the requested page or resource cannot be found at its URL.
It may be caused by a deleted page, broken link, incorrect URL, changed address, or website migration.
For good technical SEO, do not redirect every 404 automatically.
Fix broken links, restore important pages, use a 301 redirect when content has moved, maintain your XML sitemaps, and create a useful custom 404 page.
The goal is simple: make it easy for visitors and search engines to find the right content.
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