A 404 error means no page was found at the address requested. Most are harmless. The ones worth fixing are broken links on your own pages and missing pages that people still want.
A 404 error is the server's reply when no page exists at the address requested. Google says 404s on addresses that should not exist do not count against a site. Fix the ones that matter: broken links on your own pages and moved pages that people still use. Correct the link, redirect to a close match, and show a helpful error page.
What a 404 error is
A 404 error is an HTTP status code. When a browser asks a server for an address, the server replies with a three-digit code before it sends any page. The code 404 means "not found": the server is working, but it has nothing at that address. The visitor sees an error page, and search engines see the code.
The code and the page are separate things. A server can send a friendly, designed page and still attach the code 404, which is correct. It can also send a page that says "not found" with the code 200, which means "success". That mismatch is called a soft 404, and it is covered below. The table lists the codes you will meet most often.
| Code | Meaning | Typical use |
|---|---|---|
| 200 | OK, the page exists | Any normal page |
| 301 or 308 | Moved permanently | A page has a new, lasting address |
| 302 or 307 | Moved temporarily | A short-lived change, such as sending visitors elsewhere during maintenance |
| 404 | Not found | An address that does not exist, or no longer does |
| 410 | Gone | A page removed on purpose. Google's documentation says it currently treats a 410 like a 404 |
| 5xx codes | Server error | A fault on the server, which is not the same as a missing page |
Why a 404 error happens
Most 404 errors come from a short list of causes.
- A link on one of your pages has a typing mistake, or points to a page that was deleted.
- A page was renamed or moved without a redirect, so its old address now leads nowhere.
- A redesign or a change of platform produced addresses in a new pattern, and the old ones were never mapped across.
- A product, post or file was unpublished, but the pages, emails and social posts that link to it were left as they were.
- Another site, an email, a printed leaflet or a QR code carries an old or mistyped address.
- A link from your page to another website now fails because that site changed or closed.
- A bot or scanner asked for an address that has never existed on your site, such as a login page for a platform you do not use.
The last cause needs no action. Automated visitors probe every site for common addresses, so some 404s in your logs are noise. The others deserve a look, because a real person or a crawler followed a link and found nothing.
Do 404 errors hurt SEO?
Not by themselves. Google's Search Console help says 404 errors generally do not affect a site's search performance, and that you can ignore them if you are sure the addresses should not exist. A Google blog post has said the same in other words: 404s on some of your addresses do not count against the rest of your site. A deleted page leaving the index is normal.
That does not mean every 404 can be left alone. Google recommends fixing the 404 errors you link to yourself or list in a sitemap. Think about what each one costs.
- A visitor who follows a broken link on your site meets a dead end and may leave.
- A page that used to bring search visits and now returns a 404 stops bringing them, and any site that linked to it stops sending visitors.
- A sitemap that lists addresses returning a 404 sends crawlers to pages that are not there.
The real SEO risk with error pages is the soft 404. That is a page which tells the visitor the content does not exist but returns the success code 200. Google excludes soft 404s from search, and its guidance says an error page should return a true 404 status. Redirecting every missing page to the home page is not the cure. Google's documentation names that as a problem for the same reason, so send each missing address to a close match or let it return a 404.
How to find broken links on your site
No single source shows every broken link, so use two or three together.
- Open the Page indexing report in Search Console and look for the reason "Not found (404)". It lists addresses Google tried to load and could not. Inspect one with the URL Inspection tool to see how Google found it, and check the current documentation for what the tool shows.
- Run a website crawler. Free versions of desktop crawlers follow the links on your site the way a visitor would, list the status code of each address and show which page holds each broken link. Sort by status code and look at the 404s and the redirects. Include links to other sites in the crawl so dead external links show up too.
- Open the Links report in Search Console. Its table of top linked pages shows which of your addresses other sites link to. Compare it with your list of 404s, because a missing page that other sites link to is the one most worth redirecting. Google notes that the report shows a sample of links, not all of them.
- Check your analytics. If your tool records page titles, search for the title your error page uses. The report shows how often visitors land there and, depending on the tool, where they came from.
- Ask your host or developer for the most requested missing addresses in the server logs.
- Click through the site yourself: the menu, the footer, your main pages and a few older posts. After a redesign, also try a few addresses from the old site.
How to fix a broken link or a missing page
Decide what each broken address should do, one at a time. The table gives the usual answer for each case.
| Situation | Fix |
|---|---|
| A link on your page has a typing mistake | Correct the link |
| A link points to a page that has moved | Update the link to the new address, and redirect the old address in case others still use it |
| The page was replaced by a close equivalent | Redirect the old address permanently to the equivalent page |
| The page was removed and nothing similar exists | Let it return a 404 or 410 and remove the internal links to it |
| An address in your sitemap returns a 404 | Take it out of the sitemap, or restore the page |
| A link on your page to another site no longer works | Replace it with a current source, or remove the link |
| Another site links to a mistyped or old address and sends visitors | Redirect that address to the right page |
| An image, PDF or other file is missing | Restore the file, or remove the reference to it |
Use a redirect when a page has moved or been replaced by something close in purpose, and a visitor or a link would otherwise hit an error. A permanent redirect, a 301 or 308, suits a lasting move. A temporary one, a 302 or 307, suits a short-term change. Do not send unrelated pages to the home page to make an error report look tidier. The visitor wanted a particular thing, and a home page does not provide it. Planning redirects for a whole site move is a bigger job, which the website redesign SEO checklist covers.
Keep a simple list of the redirects you add, with the old address, the new address, the date and the reason. It helps when a platform changes, when someone asks why an address behaves as it does and when you want to avoid chains of redirects. Redirects are set in different places on different platforms: the content management system, a plugin or the server configuration. Ask your developer where yours live.
How to make a useful 404 page
A good 404 page helps the visitor get back on track, and it returns the status code 404.
- Say plainly that the page was not found, and that the address may have a typing mistake or may have moved.
- Keep the usual header and menu so the visitor can find their way from the page.
- Add a search box if the site has search, and links to the main sections or the most visited pages.
- Offer a way to reach you or report the problem, such as a link to the contact page.
- Use the same tone as the rest of the site. A touch of humour suits some brands and not others.
- Do not redirect the visitor away after a delay.
Google's guidance on custom error pages asks for two things: a page that helps the visitor, and a server that really returns a 404 status for it, so the page is not indexed. Google's Search Console help adds that addresses which should return a 404 must not be blocked in robots.txt. Test by typing a made-up address on your site. Check that the page looks right on a phone and that the status is 404. The network panel in a browser's developer tools shows the status code, and the URL Inspection tool in Search Console shows what Google sees.
Keep broken links from building up
Broken links come back because sites change, and a short routine keeps them down.
- Before you delete or rename a page, check what links to it and where its visitors should go instead.
- After every redesign, platform move or change of address pattern, crawl the site and test the old addresses.
- When you publish a page, test its links, including those to other sites.
- Crawl the site on a schedule, for example each quarter, and look at the 404 list in Search Console whenever you visit it.
- Name one person who owns the job, so it does not fall between the designer, the developer and the person writing content.
Finding broken links is one step in a basic SEO audit you can run yourself. If a crawl turns up errors in large numbers, or they began right after a migration, it may be time for a specialist review. The page on the signs your website needs a technical SEO audit lists what to look for, and the search engine optimisation service page describes the SEO work Liftup does.
Questions and answers
What is a 404 error?
A 404 error is the HTTP status code a server sends when it cannot find a page at the address requested. The server is working, but nothing exists at that address, perhaps because the page was deleted, moved or mistyped. Visitors see an error page.
How do I find broken links on my site?
Use the Page indexing report in Search Console to see addresses Google could not load, and run a free crawler to list broken links with the page that holds each one. Your analytics, your server logs and a quick click-through of key pages add to the picture.
Do 404 errors hurt SEO?
Google says 404 errors on addresses that should not exist generally do not affect search performance. Fix the ones you link to yourself or list in a sitemap, and make sure error pages return a true 404 code rather than a success code.
When should I use a redirect instead of leaving a 404?
Redirect when a page has moved or has a close replacement, so visitors and links reach something useful. If the page is gone and nothing similar exists, let it return a 404 or 410. Avoid sending every missing page to the home page.
What is a soft 404?
A soft 404 is a page that tells visitors the content does not exist but returns a success code. Google excludes such pages from search. Fix it by returning a real 404 status or by redirecting to a genuine equivalent page.
How do I make a useful 404 page?
Say the page was not found, keep the menu, add a search box and links to the main sections, and offer a route to the contact page. Then check that the page returns the 404 status code and not a success code.