What is 404 Error?
404 Error is an HTTP status code showing that a server can't find the resource requested by a browser or search engine. It usually appears when a page has been deleted, moved without a redirect, or entered with an incorrect URL. The response indicates that the server is reachable. But the requested resource is unavailable.
Quick Facts About 404 Error
Category
HTTP client error status
Used for
Signalling that a requested resource cannot be found
Common confusion
A 404 is different from a server failure or a 301 redirect
Also called
HTTP 404, 404 Not Found
Often discussed with
Technical SEO, SEO Audits
Key Takeaways About 404 Error
- A 404 confirms that the server responded, but the requested resource was not found.
- Broken links, deleted pages, moved content, and typing errors commonly cause 404 responses.
- A useful custom 404 page helps visitors recover instead of leaving the website.
- Relevant moved pages usually need a 301 redirect rather than a permanent 404.
- A small number of genuine 404 responses is normal. But widespread errors require investigation.
Understanding 404 Error
404 Error is an HTTP status code. It appears when a web server can't find a requested page, file, or resource. The server itself is usually available. This response differs from a 500 server error. A browser may display a standard message or a website’s custom 404 page.
Related glossary terms: 301 Redirect, Crawlability, Crawl Budget.
A 404 can result from a deleted page, changed URL, incorrect link, or typing mistake. It can also occur when a website changes its URL structure. This happens without directing old addresses to new ones. Search engines can find these responses through crawling. Users may encounter them through bookmarks, search results, advertisements, or internal links.
How 404 Error Works, Is Measured, or Is Used?
When a browser requests a URL, the request reaches the website’s server or content delivery system. The system checks whether the requested resource exists. It then returns an HTTP response code. If no matching resource is available, the server normally returns 404 Not Found. It may also include a message body. This message can explain the problem and offer navigation options.
Website owners evaluate 404 activity through server logs, Google Search Console, web analytics, and link-crawling tools. These sources help distinguish missing pages from broken internal links. They also reveal incorrect external links or software configuration issues. A 404 response isn’t automatically a problem. Permanently removed content can correctly return this status. This applies when no suitable replacement exists.
Handling depends on the cause. A relevant replacement normally receives a 301 redirect. An incorrect internal link should be fixed. A permanently unavailable resource can remain a 404. A custom error page should explain that the page isn’t available. It should preserve useful navigation. It should also avoid pretending that missing content exists.
Why 404 Error Matters?
Frequent 404 responses can interrupt journeys from search results, navigation menus, email campaigns, and external websites. Visitors may lose confidence when important pages repeatedly fail. This is especially true during product research, lead generation, or account tasks. Broken internal links also waste crawling activity. They can make a website’s content structure harder for search engines to understand.
Search engines generally don't index a genuinely missing page as normal content, but a website can create a soft 404. This happens when it returns a successful status code while showing an empty or missing page. Correct status codes, helpful redirects, and regular monitoring support better technical quality. Every old URL doesn’t need a redirect.
When 404 Error Matters Most?
404 management becomes especially important after a website migration, domain change, redesign, or content system change. These events can alter thousands of addresses. They can leave old links pointing to unavailable locations. Ecommerce websites also need careful review. Discontinued products, category changes, and seasonal landing pages can affect navigation and revenue paths.
Prioritise errors that receive external links, organic visits, conversions, or substantial internal linking. Review whether each missing URL has a close, useful replacement before applying a redirect. Sending unrelated pages to the homepage can create a poor experience. It may also be treated as a soft 404. For SEO Agency work in South Brisbane, Queensland, this review helps protect local landing pages, service enquiries, and location-specific search journeys during website changes.
How to Evaluate 404 Error?
- Check whether the response returns HTTP status 404 rather than incorrectly returning 200 for missing content.
- Review high-traffic and highly linked missing URLs before deciding between restoration, redirection, and permanent removal.
- Test internal links, navigation paths, XML sitemaps, and important external campaigns for broken destinations.
- Confirm that the custom 404 page offers search, navigation, and a clear explanation without misleading users.
- Compare server logs with Google Search Console to identify recurring patterns and newly created errors.
Related Concepts Compared
404 Error vs. 301 Redirect
A 301 tells browsers and search engines that a resource has permanently moved to another URL. A 404 states that no requested resource is currently available.
404 Error vs. 500 Server Error
A 500 error indicates that the server encountered an unexpected problem while processing a request. A 404 usually means the server worked but could not locate the requested resource.
404 Error vs. Soft 404
A soft 404 displays missing or empty content while returning a successful status such as 200. A standard 404 sends the correct not-found status.
404 Error vs. 410 Gone
A 410 indicates that a resource was intentionally removed and is not expected to return. A 404 provides a more general not-found response.
Expert Note
Do not redirect every missing URL to the homepage. A redirect is most useful when the replacement satisfies the original intent; otherwise, a clear 404 preserves accurate signals and avoids misleading visitors or search engines.
Common Mistakes or Myths About 404 Error
- Redirecting every missing URL to the homepage, even when the homepage does not match the original intent.
- Returning a 200 status for a page that only says the requested content cannot be found.
- Ignoring broken internal links because the custom 404 page looks attractive.
- Removing a page without checking its backlinks, organic visits, conversions, or sitemap references.
- Treating every 404 as a critical fault instead of assessing its source and business importance.
404 Error in Practice: A Real-World Example
A retailer removes an old product page but leaves links to its former URL. Visitors who select those links receive a 404 response. If a closely related replacement exists, the retailer can add a 301 redirect; if no equivalent exists, a helpful 404 page can guide visitors to the relevant category.
Sources & Further Reading on 404 Error
- HTTP Semantics, RFC 9110
- 404 Not Found, MDN Web Docs
- Soft 404 Errors, Google Search Central
Related Services
Related Terms
301 Redirect
301 Redirect is an HTTP response that permanently sends users and search engines from one URL…
Crawlability
Crawlability is the ability of search engine crawlers to access, discover, and retrieve pages and resources…
Crawl Budget
Crawl Budget is the number of URLs a search engine crawler can and wants to request…
Index Coverage
Index Coverage is the proportion and status of a website’s discoverable URLs that a search engine…
Best SEO Agency Brisbane
Have Questions About 404 Error?
Contact Best SEO Agency Brisbane for practical guidance on 404 Error and related seo agency work in South Brisbane.