404 Pages: Causes and Fixes

A 404 page is what a server returns when a URL does not exist. A few are harmless and unavoidable. A pile of them, especially ones your own site links to, quietly leaks trust, wastes crawl budget, and frustrates visitors. This guide explains what causes 404s, what they really cost in SEO terms, and exactly how to fix each type.

What a 404 page actually is

When a browser or Googlebot requests a URL, the server answers with an HTTP status code. A 404 is a client-error code meaning the server reached the site but could not find the specific resource. According to MDN's reference on the 404 status, links that lead to 404 responses are called "broken" or "dead" links, and a 404 signals only that the resource is missing, not whether the absence is temporary or permanent.

That distinction matters. A 404 says "not here right now." If a page is gone for good, the more precise code is 410 Gone, which tells crawlers the removal is intentional. Both are valid outcomes; the mistake is leaving important URLs returning 404 by accident, or dressing up a missing page as if it were fine. For the closely related "404 Not Found" wording and its variations, see our companion guide on 404 Not Found errors.

What causes 404 pages

Almost every 404 traces back to a URL that changed or was removed while something still pointed at the old address. The common sources are predictable.

• Deleted content that was never redirected, such as expired products, old promotions, or retired blog posts.
• Changed URLs after a redesign, CMS migration, or a change to your permalink structure.
• Mistyped or malformed links, either internal links with a typo or external sites that linked to you incorrectly.
• Case and trailing-slash mismatches, where /Page and /page or /page and /page/ are treated as different URLs.
• Broken asset references to images, scripts, or files that were moved.

Broken internal links are the most fixable category because you control both ends. Our guide to broken links goes deeper on finding and repairing them across a whole site.

The SEO impact: what 404s actually cost

A single 404 for a URL nobody links to is not a problem; Google encounters these constantly. The cost appears when 404s cluster on pages that matter. Per Google Search Central's guidance on HTTP errors, when a URL returns 404, "the indexing pipeline removes the URL from the index if it was previously indexed," newly found 404s are not processed, and crawling of that URL gradually decreases. In other words, Google drops the page and stops coming back.

The real damage is second-order. If a page had backlinks, those pass no value once the page 404s, so you lose earned authority. If your own navigation or articles link to dead URLs, you send visitors and crawlers into dead ends, which wastes crawl budget on large sites and signals neglect. And a visitor who hits a bare error page often leaves, hurting engagement for the referring page.

How to find your 404 pages

You cannot fix what you have not found, and 404s are invisible during casual browsing. Use tools that crawl systematically and report status codes at scale.

1. Google Search Console. The Pages report lists URLs excluded as "Not found (404)," which are the ones Google itself has hit. Start here; our Search Console guide explains the report in detail.
2. A site crawler. Screaming Frog's free tier crawls up to 500 URLs and flags every 4xx response along with the pages that link to it, which is exactly what you need to fix internal links.
3. A dedicated link checker. For a quick pass, a hosted broken link checker or link checker will surface dead links without installing anything.

Export the list with the source pages included. The source column tells you where to edit, which turns a vague problem into a concrete to-do list.

How to fix each type of 404

There is no single fix; the right action depends on why the URL is missing. Work through this decision order for every important 404.

• The page should still exist. Restore it, or fix the broken link that points to the wrong address. This is the answer for typos and accidental deletions.
• The content moved. Add a 301 redirect from the old URL to the new one. A 301 is a permanent redirect that, per MDN, tells browsers and search engines the resource has permanently moved and passes ranking signals to the new URL. Use a 301, not a 302, when the move is permanent.
• A close equivalent exists. 301-redirect to the most relevant live page, for example a discontinued product to its category or a newer replacement. Redirect to something genuinely related, not the homepage.
• Nothing relevant exists. Let it return 404, or better 410 Gone if the removal is permanent. This is a legitimate, healthy response; you do not need to redirect everything.

Designing a helpful 404 page

Some 404s are unavoidable, so the page users land on should help them recover rather than dead-end them. A useful custom 404 keeps your header, navigation, and branding, states clearly that the page was not found, and offers a search box plus links to popular sections. MDN recommends custom, human-friendly 404 pages for exactly this reason.

One technical caveat: your custom 404 page must still return a real 404 (or 410) status code, not a 200. If a friendly "page not found" screen returns 200 OK, Google sees a soft 404 and may index an empty page. Check the status code with a header-inspection tool, not just the visible message, because the two can disagree.

Monitoring so 404s do not pile up again

Fixing 404s once is a project; keeping them low is a habit. URLs break continuously as content is edited, products retire, and external sites relink, so a site that is clean today will drift without checks. Build a lightweight routine rather than relying on a single audit.

• Review the Search Console Pages report roughly monthly for new "Not found" entries.
• Re-crawl the site with a link checker after any redesign, migration, or bulk content change.
• Keep a redirect map so retired URLs get a 301 at the moment they are removed, not months later.

Treat continuous monitoring as part of ordinary site health. The cheapest 404 to fix is the one you catch the week it appears, before Google has dropped the page and before visitors have bounced off it.

Frequently asked questions

Do 404 pages hurt SEO?

A few isolated 404s do not hurt SEO; Google encounters them all the time. Harm comes from 404s on pages you link to internally, pages with backlinks, or pages that used to rank, because they waste crawl budget and lose earned link value. Fix those and you can safely ignore the rest.

Should I redirect a 404 page to my homepage?

No. Redirecting unrelated deleted pages to the homepage creates soft 404s that Google effectively ignores, and it frustrates users who expected specific content. Redirect only to a genuinely relevant page, and otherwise let the URL return a proper 404 or 410.

What is the difference between a 404 and a 410?

A 404 means "not found" without saying whether the absence is temporary or permanent. A 410 means "gone" and signals the removal is intentional and permanent, which can prompt Google to drop the URL a little faster. Use 410 when you have deliberately removed content for good.

How do I find all the 404 errors on my site?

Use Google Search Console's Pages report for URLs Google has hit, and a crawler such as Screaming Frog's free tier or a hosted link checker to find broken internal links along with the pages that reference them. Export the list with source URLs so you know where to make each fix.

Does a custom 404 page fix the SEO problem?

Not by itself. A custom 404 improves user experience but the underlying broken links still need fixing or redirecting. Also make sure the custom page returns a real 404 status code and not 200, otherwise Google may treat it as a soft 404 and index an empty page.

How often should I check for 404 pages?

Check Search Console roughly monthly and re-crawl the whole site after any redesign, migration, or large content change. Maintaining a redirect map so retired URLs are redirected immediately keeps new 404s from accumulating between audits.