A 404 error means a page cannot be found — the server received the request but has no content at that URL. For website owners, 404 errors are one of the most damaging and most overlooked technical SEO issues. They frustrate visitors, waste crawl budget, and signal poor site maintenance to Google. This guide covers exactly what causes 404 errors, how to find every one of them on your site, and how to fix them permanently.
What Is a 404 Error?
When a browser or search engine requests a URL that does not exist on your server, the server returns an HTTP status code of 404 — meaning "Not Found." This is different from a 500 error (server problem) or a 301 redirect (page moved). A 404 tells the requester definitively: nothing exists here.
From an SEO perspective, 404 errors matter for three reasons. First, any backlinks pointing to a 404 URL are wasting link equity — that authority is not passing to any live page. Second, Google's crawler wastes crawl budget visiting pages that return nothing. Third, users who land on a 404 page typically leave immediately, sending negative engagement signals to Google.
What Causes 404 Errors?
The most common causes of 404 errors include:
- Deleted pages — content removed without setting up a redirect
- Changed URLs — pages renamed or restructured during a redesign
- Typos in links — internal or external links with incorrect URL paths
- CMS migrations — moving from one platform to another without preserving URL structure
- Expired products or posts — pages removed when content becomes outdated
- Case sensitivity — some servers treat
/Pageand/pageas different URLs
How to Find All 404 Errors on Your Site
There are three main ways to find 404 errors:
1. Use a Broken Link Checker
Our free Broken Link Checker crawls your entire website and identifies every broken link — including internal links pointing to 404 pages and external links that have gone dead. Simply enter your domain, and within seconds you get a complete report showing every broken URL, the page it was found on, and the anchor text used. Download the results as CSV for easy tracking and fixing.
2. Check Google Search Console
Google Search Console's Coverage report shows all URLs Google has tried to crawl that returned a 404. Go to Index → Pages → Not Found (404) to see a full list. These are particularly important because they are URLs Google has actually tried to visit — meaning they either appear in your sitemap, have backlinks, or were previously indexed.
3. Check Your Server Error Logs
Your hosting provider's error logs record every 404 that occurs on your server in real time. This catches errors that crawlers and GSC might miss — for example, 404s caused by users mistyping URLs directly in their browser. Access your error log through your hosting control panel under Logs or Error Logs.
How to Fix 404 Errors
Option 1 — Set Up 301 Redirects
A 301 redirect permanently redirects one URL to another. This is the correct fix when a page has moved or been renamed. The redirect preserves the SEO value of any backlinks pointing to the old URL, passing link equity to the new destination. In WordPress, you can set up redirects using a plugin like Redirection. On other platforms, redirects are typically managed through your .htaccess file or hosting control panel.
Option 2 — Restore the Page
If the page was deleted by accident or should never have been removed, republish it. Check the Wayback Machine for a cached copy of the original content if you no longer have it.
Option 3 — Update Internal Links
If the 404 is caused by an incorrect internal link (a typo or outdated path), simply edit the link to point to the correct URL. Use our Internal Links Checker to find all internal links across your site, making it easy to spot and fix incorrect paths.
Option 4 — Create a Custom 404 Page
For 404s that cannot be redirected (random user typos, for example), a well-designed custom 404 page minimises the damage. Include your site navigation, a search box, and links to your most popular content. This keeps visitors on your site rather than bouncing back to Google.
Prioritising Which 404s to Fix First
Not all 404 errors are equally urgent. Prioritise in this order:
- 404s with backlinks — these are losing link equity every day; redirect them immediately
- 404s in your sitemap — remove or redirect these to stop wasting crawl budget
- High-traffic 404s — pages receiving organic traffic that now 404 need immediate attention
- Internal link 404s — fix these to maintain a clean site structure
- External link 404s — lower priority but worth cleaning up over time
Preventing 404 Errors in the Future
The best approach to 404 errors is preventing them in the first place. Always set up redirects before deleting or renaming pages. Run a broken link check after every major site update or content publication. Include broken link checking as part of your regular monthly SEO audit.
Summary
404 errors silently drain your site's SEO performance — wasting crawl budget, losing backlink equity, and frustrating visitors. Use our free Broken Link Checker to find every 404 on your site in seconds, prioritise fixes starting with pages that have backlinks, and set up 301 redirects to preserve link equity. Running a regular broken link audit is one of the highest-ROI technical SEO tasks you can do.