How do I find and fix 404 errors in Google Search Console?

Q: How do I find and fix 404 errors in Google Search Console?

Find 404s under Indexing > Pages as Not found (404). Here is how to tell harmless ones from costly ones and when to redirect, restore or leave a URL.

Open Indexing > Pages and look for Not found (404) among the reasons pages are not indexed. It lists URLs that returned a 404 in the past month. Many need no action: a page you removed on purpose should return 404, and Google drops it from the index on its own. The ones worth fixing are moved pages, pages other sites link to, and URLs your own site still links to.

Where 404s show up in Search Console

Page indexing report: Not found (404) lists URLs that returned 404 in the past month, with up to 1,000 examples.
URL Inspection: confirms the response for one URL and, under discovery, may show a referring page or sitemap that led Google to it.
Crawl stats: the By response breakdown shows what share of all crawl requests ended in 404 (under Settings).

Google calls a 404 "possibly good" in Crawl stats and says it is not necessary, or even desirable, to fix every one.

Which 404s to fix

Situation	What to do
The content moved to a new URL	301-redirect the old URL to the new one
You removed the page and have a close replacement	301 to the replacement, not to the homepage
You removed the page with no replacement	Leave the 404 (a 410 works the same way for Google)
Other sites link to the URL	Redirect it so those links keep working
Your own pages or sitemap link to it	Fix the links and the sitemap first
The URL never existed (a typo or a scraper's garbage)	Ignore it

Redirecting every 404 to the homepage is a common mistake. Google warns that sending many old URLs to one irrelevant destination, such as the homepage, confuses users and may be treated as a soft 404, so you gain nothing.

What a 404 does and does not do

When a URL returns a 4xx code, Google ignores its content and removes it from the index if it was indexed; crawling of that URL slows down over time. Google has said that URLs returning 404 do not affect how your other pages perform in search. The real costs are lost visitors, lost link value when other sites point at a dead page, and crawl requests spent on URLs your own site keeps linking to.

Soft 404s are the opposite problem

A soft 404 is a page that returns 200 OK but looks like an error or an empty page, such as an empty search result or a discontinued product with no content. Google reports it separately, and the fix is to return a real 404 or give the page real content. See soft 404.

A routine that keeps 404s under control

Once a month, export Not found (404) from the Page indexing report.
Sort out the URLs that once earned clicks: check them against your performance data for the last 16 months.
Check which of them have external links in the Links report.
Redirect those, fix internal links, and let the rest go.

How AutoPSEO helps

Search Console shows the 404s Googlebot met. AutoPSEO's GA4 error pages report shows the ones visitors hit, by matching page titles such as "Page not found" in your GA4 data, so you can see which broken URLs actually cost sessions. When AutoPSEO's content engine merges two articles that answer the same searches, the old address is taken down with a redirect to the page that stays, so no orphaned URL is left behind. See content engine maintenance.

Sources: Google's Page indexing report help, Crawl stats help, HTTP status codes and Google's crawlers, site moves guide and Do 404 errors hurt my site?.