A 404 error means a web page cannot be found at the URL a visitor or search engine tried to open. In plain terms, the page is missing, moved, deleted, or the address was typed incorrectly. A 404 is an HTTP status code sent by the server to say, “this page does not exist here.”
Why a 404 error matters for SEO and user experience
404 errors are normal on most websites, but unmanaged 404s can create problems. For users, they interrupt the journey and often lead to exits instead of conversions. For SEO, they can waste internal link equity, weaken crawl efficiency, and signal poor site maintenance if important pages repeatedly return 404 responses.
A few 404 pages will not automatically hurt rankings. The real issue is when valuable pages disappear without a plan, internal links point to broken URLs, or backlinks from other websites lead to missing content. In those cases, traffic, leads, and sales can be lost.
Common causes of 404 errors
Deleted or moved pages
If a page is removed or its URL changes without a redirect, visitors land on a 404 page.
Typing mistakes and broken links
Misspelled URLs, outdated menu links, and incorrect links in blog posts or emails often trigger 404 errors.
CMS or migration issues
Website redesigns, platform migrations, and slug changes can accidentally break large groups of pages.
How to fix 404 errors
Start by identifying which 404s matter most. Focus first on URLs that previously received traffic, have backlinks, or are linked from important internal pages.
Use this simple process:
1. Find the broken URL in your analytics, crawl tool, or search performance reports.
2. Check whether the page should still exist.
3. If there is a relevant replacement, add a 301 redirect to the new page.
4. If the page was removed permanently and no close replacement exists, let it stay 404.
5. Update internal links so users and crawlers stop reaching the broken URL.
6. Make sure your 404 page helps visitors continue browsing with navigation, search, and useful links.
Practical example of a 404 fix
Imagine an online store had a page called “/blue-running-shoes” that ranked well and earned backlinks. During a site update, the product page was replaced by a newer category page called “/running-shoes/blue.” If the old URL now returns a 404, users and search engines hit a dead end. The practical fix is to add a 301 redirect from the old product URL to the most relevant new page, then update any internal links pointing to the old address. This preserves more SEO value and gives shoppers a better path to purchase.
For beginners, the key rule is simple: not every 404 is a problem, but every important 404 should be reviewed quickly.