404 Error: What It Means, Does It Hurt SEO, and How to Fix It

Every website has 404 errors. Most are harmless: an old URL someone typed wrong, a link from a site that no longer exists. But some 404s are expensive. A product page that vanished after a migration. A pricing page renamed without a redirect. A navigation link pointing nowhere. Those cost you visitors, sales and search traffic, and they rarely announce themselves.

This guide explains what a 404 error is, when it matters for SEO and when it doesn't, how to find the ones worth fixing, and how to fix them properly.

What is a 404 error?#

A 404 error is an HTTP status code that means "Not Found". The server is reachable and working, but there's nothing at the URL that was requested.

Every time a browser or search engine requests a page, the server answers with a three-digit status code before it sends anything else. A 200 means the page loaded. A 301 means it moved. A 404 means it isn't there.

You'll see it written many ways: "404 Not Found", "Error 404", "HTTP 404", "Page not found", or a custom message like "Oops, we can't find that page". They all mean the same thing.

404 vs soft 404 vs 410 vs 5xx#

Not every "missing page" is the same error, and the difference matters for search engines.

Soft 404s are the sneaky one. They happen when a site shows a "page not found" message, an empty search result or a redirect to the homepage, but returns a 200 OK status. Google calls this out specifically: a page that says "404 Not Found" isn't necessarily returning a 404. Google prefers a real 404 or 410 for content that doesn't exist, and says soft 404s keep getting crawled and waste your crawl budget.

404 or 410? Google has said it treats them the same way, so either is fine for a page that's gone for good.

Do 404 errors hurt SEO?#

Not on their own. Google has been clear about this for years: 404s are a normal part of the web, and URLs on your site returning 404 don't count against your site in search results or affect how your other pages rank. You can safely ignore 404s for odd URLs that never existed on your site.

But some 404s still cost you:

• Important pages that 404 drop out of search. If a page that ranked and brought traffic starts returning 404, it will fall out of Google's index over time, along with its traffic.
• Lost link value. If other sites link to a URL that now 404s, the value of those links goes nowhere. A 301 redirect to the right page captures it.
• Lost visitors. Someone who clicks a link and hits a dead end usually leaves.
• Broken internal links waste crawling and frustrate users, and they tell visitors your site isn't maintained.

So the question isn't "how do I get rid of every 404?" It's "which 404s are hurting me?"

Common causes of 404 errors#

• Deleted pages without a redirect: discontinued products, old campaigns, expired posts.
• Changed URLs: a renamed slug, a new category structure or a CMS change, with no redirect from the old address.
• Site migrations and redesigns: whole sections of URLs change at once, and some redirects get missed.
• Broken internal links: menus, footers or old articles still pointing at pages that moved.
• Typos: in your own links, in links from other sites, or in URLs people type by hand.
• Case and trailing slash differences: on some servers /About and /about are different URLs.
• Removed files: PDFs, images and downloads deleted from the server.

How to find 404 errors#

1. Google Search Console#

In the Page indexing report, look at "Not found (404)" and "Soft 404" under the reasons pages aren't indexed. Click a reason to see example URLs, then use URL Inspection to check what Google sees for a specific page. After you fix an issue, you can ask Google to validate the fix.

2. A crawler or site audit#

A crawler follows every internal link on your site like a search engine does, and reports each one that returns a 4XX or 5XX status, along with the pages that link to it. This is the best way to find broken internal links, because it tells you exactly where to fix them.

3. Check single pages and lists of URLs#

• The free Broken Link Checker checks up to 100 internal and external links on any page and flags the ones returning 404 and other errors.
• The free Bulk URL Status Checker checks up to 20 URLs at once and shows each one's final status code, response time and any redirect hops. It's ideal for checking a list of old URLs after a migration.

4. Server logs and analytics#

Server logs show every request that got a 404, including from bots. In your analytics, filter page views by your 404 page's title (for example "Page not found") to see which missing URLs real visitors are hitting most, and where they came from.

How to fix 404 errors#

Work through your list and decide what each URL should do.

1. The page moved: 301 redirect it#

If the content now lives at a different URL, add a 301 (permanent) redirect from the old URL to the new one. Visitors land in the right place and search engines pass the old URL's signals to the new one. Use a 301, not a 302, for permanent moves. Our 301 vs 302 redirect guide explains the difference.

2. There's a close equivalent: redirect to it#

If the exact page is gone but a closely related one exists (a newer version of a product, the parent category, an updated article), redirect to that. Don't redirect everything to the homepage. Google may treat mass redirects to an unrelated page as soft 404s, and visitors get confused when they land somewhere unrelated to what they clicked.

3. The page was deleted by mistake: restore it#

If a page that brought traffic or links disappeared by accident, restoring it at the same URL is the fastest fix.

4. Fix the links pointing at it#

A redirect fixes the destination, but you should still update your own internal links to point straight at the live URL. That avoids an extra hop and keeps your site clean.

5. The page is gone for good: leave it as a 404 or 410#

If there's no replacement and nothing important links to it, a 404 or 410 is the correct answer. Google will drop it from the index over time. Just make sure it returns a real 404 status, not a soft 404.

6. Fix typos at the source#

If another site links to a misspelled version of your URL, a 301 from the misspelling to the correct page captures that traffic.

How to create a helpful custom 404 page#

You can't eliminate every 404, so make the experience good when one happens. A useful 404 page:

• Returns a real 404 status code, while still showing a friendly page
• Says clearly that the page doesn't exist, in plain language
• Keeps your normal header and navigation, so visitors aren't stranded
• Offers a search box and links to popular pages, top categories or the homepage
• Gives a way to report the broken link
• Matches your brand voice, a little personality helps, but clarity comes first

For example, an online store might show "We couldn't find that page. It may have moved or been discontinued," followed by a search bar, its best-selling categories and a link to contact support.

How to prevent 404 errors during redesigns and migrations#

Most damaging 404s happen in a single afternoon: launch day.

1. Export every URL before you change anything, from your sitemap, your crawler and your top pages in analytics and Search Console.
2. Map every old URL to its new URL in a spreadsheet before launch.
3. Set up 301 redirects from each old URL to its new home, one to one, with no chains.
4. Test the redirects right after launch. Paste your old URLs into a bulk status checker and confirm every one ends in a 200.
5. Update internal links to the new URLs.
6. Watch Search Console for new "Not found (404)" pages in the weeks after launch.

Our guide to redesigning a website without losing SEO covers the full process.

Catch new 404s the day they happen#

The worst 404s are the ones nobody notices: an important page that starts returning 404 after a deploy, a plugin update or a CMS change. Search Console can take days or weeks to report it.

MyKavo checks the HTTP status of every page you monitor on each scan. If a page that returned 200 in your approved baseline starts returning 404 or 500, it raises a critical alert right away. After each scan it also checks the internal links on your monitored pages and groups any newly broken ones into a single alert, like "17 broken internal links detected", with examples of the URLs, so you get one clear message instead of seventeen. To find broken links across the whole site, MyKavo's Site Audit crawls your pages and lists every broken internal link with the pages that link to it. Our guide on how to find broken links shows the full workflow.

The bottom line#

404 errors are a normal part of the web and don't hurt your SEO on their own. The ones that matter are important pages, pages with backlinks and broken internal links. Find them in Search Console and with a crawler, 301 redirect moved pages to their closest equivalent, fix your internal links, let truly dead pages return a real 404, and build a 404 page that helps people find their way.

Check any page for broken links now with the free Broken Link Checker, then start free with MyKavo to get a critical alert the moment an important page starts returning 404.