What Is a 404 Error? How to Find, Fix, and Prevent SEO Damage

A user clicks a link to your site — and sees a blank screen with "Page Not Found." In that moment, you've lost a visitor and sent a bad signal to Google.

The 404 error is one of the most common HTTP error codes on the internet. On its own, it's not a catastrophe — but left unchecked, it negatively impacts everything from crawl budget to link authority, user experience to conversion rates.

In this guide, you'll find step-by-step coverage of what a 404 error is, how it affects SEO, methods for finding broken links, and strategies for fixing them.

What Is a 404 Error?

HTTP 404 status code is a web server's response of "requested page not found." A browser or search engine bot sends a request to a URL; if the server can't find a page at that URL, it returns a 404 code.

HTTP status codes are three-digit numbers where the first digit indicates the response category. 2xx means success, 3xx means redirect, 4xx means client error, 5xx means server error. 404 belongs to the "4xx" client error family: the problem isn't on the server side — it's that the requested resource doesn't exist.

Why Do 404 Errors Occur?

The most common causes:

URL change: A page was moved but the old URL wasn't redirected
Page deletion: Content was removed without a redirect
Typo: A user manually typed the URL incorrectly
Broken internal links: Links within the site point to outdated URLs
Broken external links: Backlinks from other sites point to pages that no longer exist
Site migration: The URL structure changed during a domain or CMS switch
Parameter issues: Incorrectly formed URL parameters or session-based URLs
Case sensitivity: On Linux servers, /Page and /page are different URLs

Each cause has a different solution. That's why correctly identifying the source of the error comes first. Without knowing the cause, it's impossible to take the right action.

When Is a 404 Error Considered Normal?

Not every 404 signals a problem. In some scenarios, a 404 response is entirely expected and correct behavior:

Intentionally deleted content: Promotional pages that are no longer valid, expired campaigns
User-caused wrong URLs: URLs typed incorrectly into the address bar
Random URLs attempted by bots: Security scanners and spam bots try non-existent URLs

According to Google's official guidance, 404 errors don't have a direct impact on your site's crawling or ranking. But that doesn't mean you should ignore all 404s — you need to evaluate the source and impact of each one.

How 404 Errors Affect SEO

Google officially states that 404 errors are not a direct ranking factor. However, the indirect effects are serious and shouldn't be ignored.

Crawl Budget Waste

Crawl budget is the limited resource Google allocates to crawling your site. Every time Googlebot visits a 404 page, it spends that resource on an empty response instead of your actual content pages.

For small sites (a few hundred pages), the effect is negligible. But for e-commerce sites with thousands of pages or large blogs, hundreds of 404 errors can seriously waste crawl budget.

According to Google's 2025 update, URLs that return a 404 response signal to Googlebot "don't crawl this page again." This is actually positive behavior: true 404s optimize crawl budget. The real problem appears with soft 404s. We covered crawl budget management in detail in our technical SEO checklist.

Link Authority (Link Equity) Loss

Research shows that approximately 10% of existing backlinks break every year. If backlinks point to a page and that page returns a 404, the link authority earned over years is completely wasted.

To make this concrete: say a blog post has earned backlinks from 50 different sites, contributing significantly to your domain authority. If you delete that page and it returns a 404, the SEO value of all 50 backlinks becomes zero. Yet a simple 301 redirect would have preserved nearly all of that authority.

This situation directly undermines your backlink strategy. Preserving the value of every link you've earned is just as important as earning new links.

User Experience and Conversion Loss

A visitor who lands on a 404 page will almost certainly leave your site. This results in:

Higher bounce rate
Lower session duration
Lost conversion opportunities
Damage to brand credibility

We explained in detail how these metrics relate to SEO in our bounce rate guide.

404 vs. 410 vs. Soft 404: What's the Difference?

Not all "not found" errors are the same. Google responds differently to each.

Status Code	Meaning	Google's Response	When to Use
404 Not Found	Page not found (may be temporary or permanent)	Re-crawls the URL after a while, slowly drops it from index	When the page status is uncertain or temporarily inaccessible
410 Gone	Page permanently removed	Removes the URL from the index faster, reduces re-crawl frequency	When the page is consciously and permanently deleted
Soft 404	Page returns a 200 code but has no content or shows "not found" message	Wastes crawl budget, Google issues a warning	Never use — it's an error condition

Soft 404 is the most dangerous one. The server says "everything is fine" (200 OK), but there's no meaningful content on the page. When Google detects this, it issues a warning in Search Console. The real problem: Googlebot continues crawling these pages because it receives a technically "successful" response. This quietly consumes your crawl budget.

The simple rule: If a page is permanently gone, use 410. If it might come back, use 404. If it has a new address, use 301. Soft 404 is never acceptable.

How to Find 404 Errors

Using multiple tools to find broken links is the healthiest approach. Each tool offers a different perspective.

Google Search Console (Free)

Google Search Console is the most direct way to detect 404 errors.

Steps:

Sign into GSC
Go to the "Pages" (formerly Coverage) report from the left menu
Check the "Not crawled — 404 not found" and "Soft 404" filters
Review the affected URLs and prioritize them

GSC is the most reliable source because it specifically shows URLs where Google has actually crawled and found a problem.

Screaming Frog SEO Spider

Screaming Frog crawls all the URLs on your site and lists those returning 404. The free version crawls up to 500 URLs.

Advantages:

Shows both internal and external broken links
Shows which page references each broken link
Bulk export lets you take quick action

Ahrefs / Semrush Site Audit

Site audit modules in professional SEO tools automatically detect 404 errors and prioritize them by importance. Especially time-saving for large sites.

Chrome Extensions for Quick Checks

Free Chrome extensions like Check My Links and Broken Link Checker check all links on the page you're currently viewing. Ideal for small sites and checking individual pages.

Open the page, run the extension, and links highlighted in red are broken. Perfect for checking external source links in long blog posts.

Server Logs

For advanced users, server access logs provide the most comprehensive data. You can see directly which URLs Googlebot received a 404 for. This method catches problems that don't appear in GSC.

By filtering for "404" status codes in log files, you can analyze which URLs are being requested, how often, and from which sources (Googlebot, Bingbot, users).

When to Use Which Tool

Tool	Cost	Best Use Case
Google Search Console	Free	See 404s Google has detected (first step)
Screaming Frog	Free (up to 500 URLs)	Bulk detection of all internal/external broken links
Ahrefs / Semrush	Paid	Link reclamation, large site audits
Chrome Extensions	Free	Quick check of individual pages
Server Logs	Free (requires technical knowledge)	Most comprehensive, raw data analysis

We covered how these tools are used in a general SEO audit in our SEO analysis guide.

Methods for Fixing 404 Errors

Once you've found the errors, it's time to fix them. The right method varies by the type and source of the error.

301 Redirect (Permanent Redirect)

A 301 redirect permanently redirects the old URL to the new URL. It passes approximately 90-99% of link authority. The most frequently used and most effective solution.

When to use:

When a page has moved to a new URL
When the URL structure has changed
When two similar pages have been merged

How to implement (.htaccess example):

Redirect 301 /old-page https://yoursite.com/new-page

If you're using WordPress, you can manage this easily with plugins like Redirection or Rank Math. We covered these plugins in detail in our WordPress SEO guide.

Warning: Don't redirect every 404 to the homepage. Google may treat this as a "soft 404." Redirects should go to a page with related content.

302 or 301? 302 is a temporary redirect and doesn't pass link authority. Always use 301 for permanent URL changes. We highlighted incorrect redirect usage as a common mistake in our SEO mistakes guide.

Redirect chains: Avoid chaining redirects in an A → B → C pattern. Each additional redirect step both slows page loading and causes link authority loss. Every redirect should point directly to the final destination.

Recreating Content

If a deleted page still has traffic potential and is receiving backlinks, the best solution is to create new content at that URL.

You can access a copy of the old content through Wayback Machine (web.archive.org). Publishing an updated, improved version at the same URL both preserves link authority and attracts new traffic. You can use AI content writer tools to quickly create new content.

Our content refresh guide offers a step-by-step process for reviving old content.

Updating Internal Links

Fixing broken internal links on your site improves both user experience and crawling efficiency.

Process:

Use a crawling tool (Screaming Frog, Ahrefs, etc.) to identify broken internal links
Determine which page contains each broken link
Update the link to the correct URL or remove it
Re-crawl after the update to verify

Our internal linking strategy guide covers the fundamentals of building a healthy internal link structure.

Backlink Reclamation (Link Reclamation)

If external links pointing to your site return 404, you can reclaim that link authority.

Steps:

Use Ahrefs or Semrush to identify backlinks returning 404
Contact the site owner giving the link
Share the updated version of the URL
If you don't get a response, at least set up a 301 redirect to preserve the authority

This strategy is much easier and faster than earning new links — as detailed in our link building guide.

Prioritization: Which 404s Should You Fix First?

Not all 404 errors are equally important. Follow this order to make the best use of your limited time:

404 pages with backlinks — Stop the link authority bleeding (highest priority)
Pages losing organic traffic — URLs that received clicks in GSC but now return 404
404s referenced by internal links — Directly harms user experience
404s with high crawl frequency — URLs Googlebot visits repeatedly
Traffic from external sources — URLs receiving traffic from social media, email campaigns, etc.

Using Ahrefs' "Best by Links" report with a 404 filter lets you quickly identify your most-linked broken pages.

How to Design an Effective Custom 404 Page

404 errors can't be completely eliminated. Users mistype URLs, old bookmarks stop working. That's why a well-designed custom 404 page is the most effective way to save visitors who would otherwise be lost.

What a 404 Page Should Include

A clear message: "The page you're looking for wasn't found" — avoid technical jargon
Search box: Let visitors find the content they're looking for
Popular pages: Links to your most-visited pages
Homepage button: Large and prominent
Brand identity: Your logo and navigation menu should be visible
Playful touch (optional): A humorous illustration or message can soften a negative experience

What to Avoid on a Custom 404 Page

Automatically redirecting to the homepage (confuses users)
Leaving the page completely blank
Giving no information beyond "404 Error"
Removing navigation (visitors need to be able to return to the site)

A good 404 page significantly reduces bounce rate and keeps visitors on your site.

Real-World 404 Page Examples

The most successful 404 pages have one thing in common: they redirect users in a helpful way without blaming them.

GitHub: Uses a playful Star Wars-themed parallax illustration on their 404 page. Fun, but it also has a search box and navigation menu.

Airbnb: Pairs the message "Sorry, this page seems to have gotten lost" with links to popular destinations. Guides users toward searching.

Lego: Shows a sad Lego character on their 404 page. Simple, on-brand, and includes a strong CTA back to the homepage.

The common thread: all provide an experience aligned with the brand, aiming to keep visitors rather than lose them.

Preventing 404s During Site Migrations and URL Changes

Site migration is the riskiest SEO operation — done wrong, it can cause hundreds or even thousands of 404 errors.

Pre-Migration Checklist

Create a full URL map: Build a matching table of Old URL → New URL
Prioritize traffic-getting pages: Identify the most-trafficked pages from GSC and Analytics data
Export your backlink profile: Pages receiving external links must be included in the redirect list
Create a 301 redirect plan: Determine the corresponding new URL for every old URL

Post-Migration Monitoring

Check GSC for crawl errors daily (the first 2-4 weeks are critical)
Track ranking changes for your target keywords with the free rank checker
Closely monitor organic traffic changes
Distinguish drops caused by migration from Google algorithm updates
Quickly identify and fix unredirected old URLs

Our SEO-friendly site architecture and URL structure guide covers all the technical details you need to watch for when changing URLs.

CMS Change Considerations

When switching from WordPress to another CMS (or vice versa), the URL structure typically changes. Permalink structure, category slugs, and media URLs in particular tend to differ.

In these transitions, regex-based bulk 301 redirects are far more efficient than matching URLs one by one.

Product Page 404s on E-commerce Sites

On e-commerce sites, product pages for out-of-stock or discontinued items are the most common source of 404s. The correct way to manage these pages:

Temporarily out of stock: Keep the page live, show an "out of stock" message, suggest similar products
Permanently discontinued product: 301 redirect to a similar product in the same category or to the category page itself
Entire category removed: Redirect to the parent category or a main category

We covered the SEO dimensions of product page management in our ecommerce SEO guide.

Automated Technical SEO Monitoring

Manually detecting broken links and 404 errors is a time-consuming process that requires regular maintenance. As page count grows, manual checking ceases to be sustainable.

DexterGPT's automated technical SEO audit module regularly crawls your site and automatically detects 404 errors, broken internal links, and redirect chains. In a single report, you can see which URLs are problematic, which pages reference broken links, and the recommended fixes.

The site health monitoring feature lets you notice newly appearing 404 errors in real time, so you can intervene before problems grow. Explore DexterGPT's full features to discover the details of technical SEO auditing.

Use our free SEO analysis tool to quickly scan your site and identify your current 404 errors and broken links.

Frequently Asked Questions

Does a 404 error lower my Google ranking?

Not directly. Google has officially stated that 404 errors are not a ranking factor on their own. However, the indirect effects — link authority loss, poor user experience, crawl budget waste — can negatively impact your rankings over time. Pages with backlinks returning 404 in particular cause serious authority loss.

Should I use 404 or 410?

If a page has been permanently removed and won't come back, use 410. Google recognizes the 410 code faster than 404 and removes that URL from the index more quickly. Use 404 for situations where the page might return or for temporary inaccessibility.

Is it correct to redirect all 404 pages to the homepage?

No — this is a common mistake. Google may treat redirects that are irrelevant to the original content as "soft 404s." Redirect each 404 URL to the most contextually relevant page. If there's no relevant page, showing a well-designed 404 page is a better option.

What is a soft 404 and why is it dangerous?

A soft 404 occurs when the server returns a 200 (success) code but the page content is empty or shows a "not found" message. Googlebot continues crawling these pages because it receives a technically "successful" response — silently consuming your crawl budget. If you see a "Soft 404" warning in GSC, either fix those pages to actually return a proper 404 or redirect them with a 301.

How often should 404 errors be checked?

For sites actively publishing content, a weekly GSC check is recommended. After site migrations or major URL changes, check daily for the first 2-4 weeks. Monthly full site crawls (with Screaming Frog or similar tools) are best practice. You can also use a word counter to verify that recreated pages have sufficient content. Our SEO KPI and reporting guide helps you put these checks on a regular schedule.