404 Not Found: The Most Famous HTTP Error
Common Causes of 404 Errors
| Cause | Example | How to Fix |
|---|---|---|
| Typo in URL | example.com/abot-us instead of /about-us | Check the spelling, use a search box or navigation menu. |
| Broken link | An external or internal link points to a page that no longer exists. | Update or remove the link; set up a redirect if the page was moved. |
| Page deleted without redirect | Content was removed, but no 301 or 410 was set up. | Use 301 redirect to a relevant page, or 410 if permanently gone. |
| URL case sensitivity | Some servers are case‑sensitive; /About vs /about. | Normalize URLs to lowercase, or use rewrite rules. |
| Missing trailing slash | Server expects /directory/ but receives /directory. | Configure server to handle both or use canonical URLs. |
| Expired cache/DNS | Old DNS records or stale CDN cache can cause 404 for valid resources. | Clear cache, update DNS, or wait for propagation. |
404 vs. 410 Gone
Both indicate that the resource is not available, but they have a subtle difference:
- 404 Not Found – the resource might exist in the future (it's temporarily or permanently missing, but the server doesn't know).
- 410 Gone – the resource has been permanently removed and will not be available again. This is useful for SEO because search engines can de‑index the URL faster.
Example: 404 Response
Building a Great Custom 404 Page
A well‑designed 404 page can keep visitors on your site and reduce bounce rates. Best practices:
- Keep the design consistent – match your site's branding.
- Include a search bar – let users find what they're looking for.
- Provide navigation links – link to popular pages, categories, or the homepage.
- Add a funny or friendly message – it softens the frustration.
- Monitor 404 errors – use Google Search Console or analytics to track broken links and fix them.
SEO Best Practices for 404s
- Minimize 404s – regularly audit your site for broken links.
- Use 301 redirects – for permanently moved content, redirect to the new URL.
- Use 410 Gone – for permanently deleted content to speed up de‑indexing.
- Don't block search engines – allow them to crawl your 404 pages so they can discover redirects.
- Custom 404 with helpful links – helps retain users and signals a good user experience to search engines.
Frequently Asked Questions
Why do I get a 404 error even when the page exists?
This can happen due to URL case sensitivity, missing trailing slashes, or a server misconfiguration. Also, your browser cache or DNS may be outdated. Try clearing your cache, using a different browser, or accessing the page with a different URL format.
Does a 404 error hurt SEO?
A few 404s are normal, but many can harm your SEO because they indicate a poor user experience and broken links. Search engines may reduce your crawl budget. Regularly fix or redirect 404s to maintain a healthy site.
Should I return 404 or 410 for deleted pages?
Use 410 if the page is permanently gone and you won't bring it back. This tells search engines to de‑index the URL faster. For pages that might return, use 404. For moved pages, use 301 redirects.