A 404 error is an HTTP status code the server returns when it cannot find a page at the requested URL. It signals that the resource does not exist — either because it was deleted, renamed, or never existed. 404s do not directly hurt SEO in small numbers, but at scale they waste crawl budget and strand link equity from backlinks pointing to dead URLs.
Every site produces 404s. The problem isn't that they happen — it's that most site owners never notice which URLs are broken, and which of those had backlinks or organic traffic attached to them.
What is a 404 error?
A 404 error is a client-error HTTP response code. When a browser or crawler asks for a URL and the server can't find a matching resource, it returns 404 Not Found. The visitor typically sees an error page, and search engines record the URL as unavailable.
404s are one of five HTTP response-code families:
- 1xx — informational
- 2xx — success (e.g. 200 OK)
- 3xx — redirection (e.g. 301, 302)
- 4xx — client errors (e.g. 404, 410, 403)
- 5xx — server errors (e.g. 500, 503)
Google has stated publicly that 404s are a normal part of the web and having some 404s does not harm your site. What matters is that legitimate URLs return 200 and retired URLs return the correct 404 or 410. Do not fake 200 responses on missing pages — that creates soft 404s.
Why 404 errors matter for SEO
A single 404 on a page nobody links to is invisible. Hundreds of 404s across a site — especially on pages that had backlinks or ranked — quietly erode organic performance.
- Lost link equity. External backlinks pointing to a 404 pass zero ranking power. Every uncorrected 404 with backlinks is authority you already earned and are now wasting.
- Wasted crawl budget. Googlebot spends time re-checking dead URLs instead of indexing your real content. On large sites this delays fresh pages from getting indexed.
- Broken user journeys. Users who hit a 404 bounce at rates 2-3x higher than users who land on a working page. Internal 404s in navigation or content can block visitors from reaching key pages entirely.
- Ranking loss on the wider URL. A 404 on a page that used to rank means the ranking disappears within days to weeks. If that page had earned position 3 for a competitive keyword, the position is gone.
How a 404 error works
The exchange is a short one — the server can't fulfil the request, so it says so.
GET /blog/deleted-post/ HTTP/1.1
Host: example.com
# Server can find no matching resource
HTTP/1.1 404 Not Found
Content-Type: text/html
# Body is your custom 404 page
Hard 404 vs soft 404
A hard 404 returns the proper HTTP 404 status code — the correct behaviour. A soft 404 returns a 200 OK status but shows a "page not found" message in the body. Soft 404s confuse search engines into indexing an effectively empty page.
Google Search Console flags soft 404s separately in the Pages report because they waste crawl budget and pollute the index.
404 vs the other error responses
| Status | Meaning | When to use | SEO handling |
|---|---|---|---|
| 404 Not Found | Resource not found (may exist later) | Deleted, renamed, or bad URL | Removed from index over time |
| 410 Gone | Resource intentionally removed | Retired content, no replacement | De-indexed slightly faster than 404 |
| 301 Redirect | Permanently moved | Content moved to new URL | Passes link equity to new URL |
| 403 Forbidden | Access denied | Auth-required or blocked resource | De-indexed similarly to 404 |
| Soft 404 | Empty page but 200 OK | Bug — should never ship | Fix immediately, wastes crawl |
Real 404 error examples
1. A redesigned site with new URL structure
A law firm changes /services/personal-injury-attorney/ to /practice-areas/personal-injury/. Without 301s, every existing link and bookmark hits a 404. The old page had ranked #3 for its target keyword — that ranking evaporates within weeks and the 47 backlinks pointing to the old URL now flow to a dead end.
2. A deleted blog post with backlinks
An accounting firm removes an outdated tax guide that had earned 40+ backlinks over five years. The URL now 404s. A 301 to the updated version would have preserved the link equity and kept the page ranking. Instead, the authority evaporates.
3. Typo in a promoted campaign URL
A launch email links to /product-lauch/ instead of /product-launch/. Every click 404s. This is where a well-designed custom 404 page with search plus popular links earns its keep — visitors can still find what they wanted.
4. Faceted URL exploding
An ecommerce site's filter combinations generate thousands of unique URLs. When inventory shifts, many combinations become 404s. If those URLs made it into Google's index, crawl budget gets burned on dead facets.
404 vs 301 redirect — which to use
The decision comes down to whether the retired URL has a valid replacement.
Return a 404 (or 410) when
- The page is gone with no equivalent replacement
- Nothing on your site matches the intent
- The URL was a mistake in the first place
- Content is out of date and not worth keeping
- Facet or filter combinations no longer valid
Use a 301 redirect when
- Equivalent content exists at a new URL
- The page had backlinks or organic traffic
- You changed the URL structure or slug
- You merged two pages into one
- You migrated to a new domain
7 best practices for handling 404 errors
- Audit for 404s monthly. Google Search Console's Pages report and tools like Ahrefs Site Audit surface broken URLs. Fix the ones with backlinks or internal links first.
- Design a helpful custom 404 page. Include your logo, a clear "not found" message, a site search bar, and links to your most popular sections. Don't dead-end the visitor.
- Return the correct HTTP status. Custom 404 pages must return an actual 404 status code, not 200. Test with
curl -I. - Redirect only to relevant destinations. If the retired URL has a natural equivalent, 301 to it. If not, let the 404 stand — mass redirects to the homepage create soft 404s.
- Track 404s in analytics. Tag your 404 page in GA4 so you see which URLs are being hit most. Those are your top fix candidates.
- Fix internal links first. External backlinks you don't control. Internal links you do. Broken internal links are the fastest 404 wins.
- Use 410 for permanent retirements. If a page is gone forever with no replacement, return a 410 Gone instead of a 404. Google de-indexes it slightly faster.
A custom 404 page that returns HTTP 200 is one of the most common technical SEO bugs. Google indexes it as a real page but shows "duplicate without user-selected canonical" in Search Console. Test every 404 URL with curl -I and confirm the status line reads HTTP/1.1 404 Not Found.
Common 404 mistakes to avoid
- Ignoring 404s until rankings drop — by then you're playing catch-up.
- Mass-redirecting 404s to the homepage — treated as soft 404s and given no value.
- Custom 404 page returning 200 — creates a soft 404 and pollutes the index.
- Leaving broken internal links live — they multiply into more 404 hits every day.
- Not using 410 for truly retired content — slows the de-indexing process.
- Blocking 404 URLs in robots.txt — prevents Google from seeing they are 404 and re-crawling. Let Google see the 404.
Frequently asked questions
Individual 404s on low-value pages will not tank rankings — Google confirms that some 404s are a normal part of the web. Large numbers of 404s, especially on pages with backlinks or internal links, do waste crawl budget and can signal poor site maintenance.
Google Search Console's Pages report lists URLs returning 404s under "Not found (404)". Third-party crawlers like Screaming Frog and Ahrefs Site Audit scan every URL on your site and flag broken pages within minutes.
Only redirect 404s to relevant pages. Redirecting deleted pages to your homepage creates a bad user experience and Google may treat those redirects as soft 404s anyway. If there is no logical destination, let the 404 stand or return a 410 Gone.
A hard 404 returns the proper HTTP 404 status code. A soft 404 returns HTTP 200 OK but shows a "page not found" message, which confuses search engines into indexing an empty page. Soft 404s waste crawl budget and Search Console flags them separately.
A 404 says "not found — might come back." A 410 says "gone forever." Google removes 410 URLs from the index slightly faster than 404s. Use 410 for content you have permanently retired with no replacement.
Related glossary terms
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