A website can lose traffic without experiencing a major ranking penalty or a visible server failure. Sometimes the problem is much simpler: visitors and search engine crawlers are reaching URLs that no longer exist.
These URLs usually return a 404 Not Found status. A few 404 errors are normal on almost every website. The problem starts when broken URLs become common, especially when they affect important pages, internal links, backlinks, or URLs that previously received organic traffic.
A 404 error means the server could not find the requested resource. It does not automatically mean that a website has an SEO problem. The correct response depends on why the URL is returning 404, whether the page should still exist, and whether there is a relevant replacement.
This guide explains how to find 404 errors, decide which ones need fixing, choose between 301 redirects and 410 responses, create a useful custom 404 page, and prevent broken URLs from accumulating.
Key Takeaways
- A 404 means the requested URL cannot be found on the server.
- Not every 404 needs to be redirected.
- Use a 301 redirect when a relevant replacement page exists.
- A 410 response can be used when content has been permanently removed with no replacement.
- Broken internal links should usually be fixed at the source.
- Important backlinks pointing to deleted URLs may justify a redirect.
- Regular site crawls can catch broken links before they affect users.
What Is a 404 Error?
A 404 Not Found error is an HTTP status response indicating that the server cannot find the resource requested at a particular URL.
For example, suppose a website previously had this page:
polyvalent.com/services/seo-audit
The page is later deleted, but someone visits the old URL. If the server cannot find a resource at that address, it can return a 404 response.
A 404 can happen because:
- A page was deleted
- A URL was changed
- An internal link contains a typo
- An old URL was removed during a redesign
- A product or service was discontinued
- An external website still links to an old URL
- A page was moved without a redirect
- A URL was incorrectly entered by a visitor
The important distinction is between an expected 404 and a broken 404.
If a page was intentionally removed and has no useful replacement, returning 404 can be perfectly appropriate. If a valuable page was moved to a new URL and the old address now returns 404, the situation should usually be corrected.
Are 404 Errors Bad for SEO?
A 404 error by itself is not automatically harmful to SEO.
Search engines expect websites to contain URLs that disappear over time. The problem is the underlying situation that caused the 404.
For example, a deleted page with no traffic, no backlinks, and no relevant replacement may not require any action.
A different case is an important service page that used to rank for valuable keywords and receive links from other websites. Allowing that URL to return 404 without considering a replacement can result in lost traffic and missed link value.
Broken internal links are another concern. When a page on your website links to a URL that returns 404, users encounter a dead end. Search engine crawlers encounter the same broken path.
That is why 404 management should be based on the value and purpose of the URL rather than the number of errors alone.
How to Find 404 Errors on Your Website
Finding broken URLs is the first step. The best approach is to combine search engine data with a complete website crawl.
Google Search Console
Google Search Console can reveal URLs that Google has encountered and that are returning errors.
Review the indexing reports and inspect individual URLs to understand whether the page is currently accessible, indexed, redirected, or returning an error.
Search Console is particularly useful because it shows problems from Google’s crawling perspective rather than only from the website’s internal link structure.
Website Crawlers
Tools such as Screaming Frog, Sitebulb, Semrush, and Ahrefs can crawl a website and identify links returning 404 responses.
A crawl can reveal:
- Broken internal links
- Broken external links
- Deleted pages still referenced internally
- Redirects
- Redirect chains
- Broken images and resources
- URLs returning server errors
For large websites, a crawler is often much faster than checking URLs manually.
Server Logs
Server logs provide another layer of information.
They can show which URLs are actually being requested, including URLs that may not appear in your current internal linking structure. This can reveal old URLs still being visited by search bots, users, or external websites.
Manual Checks
Manual testing is still useful when investigating a specific URL.
Open the URL directly and check the HTTP response. Browser developer tools can help confirm the status code and identify whether other resources on the page are failing.
How to Fix a 404 Error
There is no single fix for every 404. The correct solution depends on what happened to the original page.
1. Fix the Internal Link
If the page still exists but an internal link points to the wrong URL, correct the link.
For example:
/services/seo-audi
may have been linked instead of:
/services/seo-audit
In this situation, there is no reason to create a redirect. Correct the source link so users and crawlers reach the intended page directly.
2. Use a 301 Redirect When a Relevant Replacement Exists
A 301 redirect tells browsers and search engines that a URL has permanently moved to another location.
Use a 301 when the old page has a genuine replacement.
For example:
/old-seo-guide → /seo-guide
A redirect makes sense when:
- A URL has changed
- A website has been migrated
- A page has been consolidated
- A product has moved to a new URL
- An old article has been replaced by a substantially relevant updated page
The destination should match the original page’s purpose as closely as possible.
Redirecting every deleted URL to the homepage is not a good substitute for proper URL management. If the homepage does not satisfy the intent of the old page, the redirect provides little value to the user.
3. Use 410 When Content Is Permanently Gone
A 410 Gone response can be used when a resource has been intentionally and permanently removed and there is no relevant replacement.
The distinction is useful:
- 404: The requested resource was not found.
- 410: The resource has been intentionally removed and is no longer available.
For example, a discontinued campaign page with no replacement may reasonably return 410.
This provides a clearer signal that the URL is permanently gone rather than temporarily unavailable.
4. Remove Dead URLs From XML Sitemaps
Your XML sitemap should contain URLs that you want search engines to discover and consider.
A deleted URL returning 404 or 410 should generally not remain in the sitemap.
Keeping removed URLs in the sitemap creates conflicting signals. The sitemap effectively says, “Here is a URL you should know about,” while the server responds, “This URL does not exist.”
After deleting or changing URLs, review the sitemap and remove obsolete entries.
5. Update External Links Where Possible
Sometimes a broken URL still receives valuable referral traffic or backlinks.
If another website links to an old page on your domain, check whether the old page has a suitable replacement.
If it does, a 301 redirect can preserve the user journey. In cases where the referring website is important and accessible, you can also contact its owner and request that the link be updated.
This is particularly useful after major website migrations, URL restructures, or content consolidation.
301 Redirect vs 404 vs 410
Choosing the right response is easier when the purpose of the old URL is clear.
| Situation | Recommended response |
| Page still exists but link is incorrect | Fix the link |
| Page moved to a relevant new URL | 301 redirect |
| Several pages consolidated into one relevant page | 301 redirect |
| Page permanently removed with no replacement | 410 or 404 |
| Temporary server problem | Fix the server issue |
| Deleted page has a strong relevant replacement | 301 redirect |
| Random URL or typo with no useful destination | 404 |
The goal is not to eliminate every 404 response. The goal is to make sure every important URL has the correct response.
How 404 Errors Happen During Website Migration
Website migrations are one of the most common sources of broken URLs.
Changing the CMS, domain structure, category system, permalink format, or website architecture can create hundreds or thousands of old URLs.
For example:
Old structure
/blog/seo-guide
New structure
/resources/seo-guide
If the old URL is simply deleted, users who have bookmarked it, search engines that know about it, and external websites linking to it may encounter a 404.
This is why redirect mapping should happen before a migration goes live.
Create a spreadsheet containing:
| Old URL | New URL | Redirect Type | Status |
| /old-page | /new-page | 301 | Tested |
| /old-service | /services/new-service | 301 | Tested |
| /expired-offer | None | 410 | Tested |
After launch, crawl the new website and verify that important old URLs resolve correctly.
A proper migration audit should not stop at redirects. Review internal links, XML sitemaps, canonical URLs, indexation, and navigation as well.
Designing a Useful Custom 404 Page
Even with careful maintenance, visitors will occasionally reach a URL that does not exist.
A custom 404 page gives them a way forward.
A basic server error saying only “404 Not Found” provides no context and no useful next action. A well-designed 404 page can turn that dead end into another opportunity to continue browsing.
What Should a Custom 404 Page Include?
Clear messaging
Tell the visitor that the page cannot be found without blaming the user.
Search functionality
A search bar can help visitors find the information they originally wanted.
Useful navigation
Include links to important sections such as services, products, resources, or the homepage.
Relevant content
Popular articles, categories, or frequently visited pages can give users another route.
A clear CTA
If the website is designed to generate enquiries, include an appropriate contact or consultation option.
The 404 page should still return an actual 404 HTTP status. A visually friendly error page should not pretend that the missing URL exists.
Best Practices for Preventing 404 Errors
Fixing broken URLs is useful, but preventing them is better.
Plan Redirects Before Website Changes
Whenever URLs will change, prepare a redirect map before the new website goes live.
This is especially important for:
- Website redesigns
- CMS migrations
- Domain changes
- URL structure changes
- Content consolidation
- Category restructuring
Do not wait until traffic drops to start investigating old URLs.
Audit Internal Links Regularly
Broken internal links are often a symptom of a larger site-architecture problem. When URLs change, links across older articles, service pages, category pages, and navigation elements can continue pointing to the previous address. This is why internal links should be reviewed whenever URLs are changed, rather than waiting for a crawler to report them as broken.
Crawl the Website Regularly
A quarterly crawl is a reasonable starting point for many websites, while larger or frequently updated websites may benefit from more frequent checks.
Look for:
- 4xx errors
- 5xx errors
- Redirect chains
- Redirect loops
- Broken internal links
- Broken external links
- URLs in the sitemap returning errors
A technical SEO audit should treat broken links as one part of the wider website health check rather than as an isolated problem.
Monitor Important External Links
Not every external backlink can be controlled, but valuable referring links can be monitored.
If a high-quality website links to a URL that has been deleted, determine whether the old page should redirect to a relevant replacement.
This can recover referral opportunities while preserving a cleaner user journey.
404 Errors and AI Search Visibility
Website accessibility matters beyond traditional search.
AI-powered search systems and answer engines need to retrieve and process information from accessible web pages. If important content disappears, returns errors, or becomes difficult to discover through the site’s structure, its availability for retrieval can be affected.
This does not mean every 404 directly causes an AI visibility problem. The more practical concern is broader technical accessibility.
A site that consistently maintains working URLs, clear internal links, accurate sitemaps, and accessible content gives search crawlers and other retrieval systems a cleaner source to work with.
This is one reason broken URLs should be considered alongside other technical SEO issues rather than treated as a purely cosmetic website problem.
A Practical 404 Audit Checklist
Before closing a 404 issue, ask:
- Does the page still need to exist?
- Is there a genuinely relevant replacement?
- Should the old URL return 301, 404, or 410?
- Are any internal links still pointing to it?
- Is the URL still present in the XML sitemap?
- Does the URL have valuable backlinks?
- Did the error appear after a website migration?
- Are there similar broken URLs elsewhere on the site?
- Does the custom 404 page help users continue their journey?
- Has the fix been tested after implementation?
The answers will usually make the correct action clear.
Frequently Asked Questions
1. What does a 404 error mean?
A 404 means the server cannot find the resource requested at that URL. The URL may have been deleted, moved, mistyped, or incorrectly linked.
2. Are 404 errors bad for SEO?
Not necessarily. A small number of expected 404s is normal. Problems arise when valuable pages, internal links, or important URLs return 404 without an appropriate solution.
3. Should every 404 URL be redirected?
No. Redirect a 404 when there is a relevant replacement. If no suitable replacement exists, keeping the URL as 404 or using 410 may be more appropriate.
4. What is the difference between 301 and 404?
A 301 tells search engines and browsers that a page has permanently moved to another URL. A 404 says that the requested resource cannot be found.
5. What is a 410 error?
410 Gone indicates that a resource has been permanently removed. It can be appropriate when a page has no replacement and the removal is intentional.
6. How can I find broken links on my website?
Google Search Console, Screaming Frog, Sitebulb, Semrush, and Ahrefs can help identify URLs returning 404 responses. Server logs can provide additional information about requests to missing URLs.
7. Can broken internal links hurt user experience?
Yes. A broken internal link takes visitors to a page that does not exist, interrupting their journey and potentially preventing them from reaching important information.
8. Should 404 pages be included in an XML sitemap?
No. XML sitemaps should contain the URLs you want search engines to discover and process. Deleted URLs returning 404 or 410 should generally be removed.
9. How often should I check for 404 errors?
A quarterly crawl is a useful baseline for many websites. Websites that publish frequently, change products regularly, or undergo development work may need more frequent monitoring.
10. How do I prevent 404 errors during a website migration?
Create a URL redirect map before launch, redirect old URLs to relevant new destinations, update internal links, remove obsolete sitemap entries, and crawl the new website after launch to verify the implementation.
Conclusion
404 errors are not automatically a sign of poor SEO. The real issue is failing to understand why a URL is broken and what should happen to it.
Some URLs should be corrected. Some should redirect to a relevant replacement. Others should remain 404 or return 410 because the content is genuinely gone.
The best approach is proactive. Monitor broken links, maintain clean internal linking, keep XML sitemaps accurate, plan redirects before migrations, and review important URLs regularly.
A technically healthy website does not need to eliminate every 404. It needs to make sure that valuable pages remain accessible and that removed pages return the response that best reflects their current status.