Client Error

HTTP 404 Not Found

The requested resource could not be found on the server — the page may have been deleted, moved, or the URL was typed incorrectly.

Check a URL for HTTP 404

Paste any URL to see whether it currently returns 404. Runs a live HTTP probe and follows redirects.

TL;DR

A 404 means the page is missing. Fix the ones that matter (pages with backlinks, traffic, or internal links) by redirecting them with a 301 to the closest live equivalent. Ignore the noise (random scraper URLs, /wp-admin probes on a non-WordPress site). A custom 404 page should help the user find what they were looking for, not just say "not found."

What does HTTP 404 mean?

HTTP 404 Not Found is the most recognised error code on the web. It tells the client that the server reached but could not find anything matching the requested URL. A 404 does not mean the server is broken — it simply means the path doesn't map to a resource. A small number of 404s is unavoidable (mistyped URLs, expired campaign links, scraper noise). A large or growing number is a warning sign: deleted pages without redirects, broken internal links, a botched migration, or a CMS misconfiguration.

Common Causes

•Page deleted without a 301 redirect to its replacement
•URL structure changed during a redesign or CMS migration
•Internal link points to an old or typo'd path
•External backlinks pointing to URLs that no longer exist
•Bots and scanners probing for common paths (/wp-admin, /.env, /admin)
•Trailing-slash mismatch (/about/ vs /about) when the server isn't configured to normalise
•Case-sensitivity issues (/About vs /about on Linux servers)

How to Fix It

1.Export your 404 log from Google Search Console (Coverage → Excluded → Not found 404) and from your CDN/server logs
2.For each 404 with traffic or backlinks, add a 301 redirect to the closest live equivalent page
3.Run a crawler (Screaming Frog, Sitebulb, or LemWatch's broken link checker) to find internal links pointing to 404s and fix them at the source
4.Build a useful custom 404 page: site search, top categories, recent articles, contact link — not just a dead-end message
5.Submit an updated XML sitemap so Google re-crawls the corrected structure
6.Don't blanket-redirect every 404 to the homepage — Google calls this a "soft 404" and treats it as worse than a clean 404
7.For paths that should genuinely be gone forever (deleted product, retired campaign), return 410 Gone instead of 404 so Google deindexes faster

SEO Impact

High SEO impact. 404s waste crawl budget (Googlebot stops crawling broken paths but keeps re-checking them), drop the link equity of inbound backlinks (a backlink to a 404 page gives you nothing), and erode user trust. Google does not penalise sites for having some 404s — it expects them — but it does penalise sites with a high proportion of broken internal links or large numbers of previously-indexed pages now returning 404 without redirects. Sites that migrate without redirects routinely lose 40-80% of organic traffic.

Monitor HTTP 404 with LemWatch

LemWatch crawls your site continuously, catches new 404s the moment they appear, and groups them by source (which page links to the broken URL). It also monitors that pages previously returning 200 don't silently start returning 404 — a classic sign of a botched deploy.

History & Context

HTTP 404 was defined in the original HTTP/1.0 spec (RFC 1945, 1996) and carried into HTTP/1.1 (RFC 2616, 1999, now obsoleted by RFC 9110). The urban legend that 404 is named after "room 404 at CERN where the original web server lived" is a hoax — the code is simply the fourth defined client-error code (400, 401, 403, 404). The cultural impact is real though: 404 has become shorthand for any missing thing online.

Real-World Examples

GitHub's Octocat 404

github.com/this-page-does-not-exist returns a 404 with a parallax Octocat illustration — widely cited as the gold standard for a branded 404 experience.

WordPress site migrations

Switching permalink structures (/?p=123 → /post-slug) without redirects is the single most common cause of mass 404s on small sites — typically 60-90% of traffic disappears within weeks.

E-commerce category pruning

Shopify and WooCommerce stores that delete out-of-stock products without redirects lose long-tail organic traffic and the link equity of any backlinks pointing to those product pages.

Nginx: redirect old URLs to new and serve a custom 404

nginx

# Redirect specific deleted pages to their closest equivalent.
location = /old-product-name { return 301 /products/new-name; }
location = /2020/launch-blog { return 301 /blog/launch; }

# For everything else that's genuinely gone, serve a useful 404.
error_page 404 /404.html;
location = /404.html {
    root /var/www/html;
    internal;
}

Frequently Asked Questions about HTTP 404

What does HTTP 404 mean?

HTTP 404 Not Found means the server reached successfully but couldn't find anything at the requested URL. It is a client-error code, indicating the URL doesn't map to a resource — not that the server itself is broken.

Why am I seeing 404 errors on my own website?

Usually one of: deleted pages without redirects, a URL structure change during a redesign, broken internal links pointing to old URLs, or bots probing for paths that don't exist. Check Google Search Console under Coverage → Excluded → Not found 404 to see which 404s Google is encountering.

How do I fix a 404 error?

If the page should exist: restore it or redirect (301) the URL to the closest live equivalent. If it shouldn't exist: leave it as a 404, or use 410 Gone to tell Google it's permanently removed. Always fix the source of the link (internal navigation, sitemap, external citation) where possible.

Are 404 errors bad for SEO?

A few are fine — Google expects them. Many are a problem because they waste crawl budget and lose link equity. The real SEO damage comes from migrating a site without redirects, which can erase 40-80% of organic traffic within months.

Should I redirect 404s to the homepage?

No. Google calls this a "soft 404" and treats it as worse than a clean 404 because it pollutes the index with duplicate homepage entries. Redirect each missing URL to its closest specific match, or let it return 404 honestly.

404 vs 410 — which should I use?

404 says "not found right now" (might come back). 410 says "permanently gone" (will not come back). Google deindexes 410 pages faster than 404s. Use 410 for deleted products, retired campaigns, and removed content; use 404 for the catch-all.

What should a good 404 page contain?

A clear message that the page is missing, a working site search box, links to top categories or recent content, a homepage link, and (optionally) a way to report the broken link. Avoid generic "Oops, something went wrong" messaging that doesn't help the user.

Does a 404 hurt my Google ranking?

A single 404 doesn't hurt rankings directly. A pattern of 404s — especially on previously-indexed, link-bearing pages — does. Google interprets it as poor site maintenance and reduces crawl frequency. Fix the high-value 404s and ignore the noise.