How to find 404 errors on a website
You can't fix broken URLs you don't know about. 404s bleed traffic and rankings quietly, so the first step is finding them. Here are five reliable ways to surface every 404 on your site, from free tools to real-time monitoring.
Five ways to find 404 errors on your site
- 1
Google Search Console (free)
Open the Pages report under Indexing and look for 'Not found (404)'. This shows URLs Google tried to crawl and couldn't — the ones actively hurting your search presence. It's the best free starting point.
- 2
Crawl your site with an SEO tool
Run a crawler like Screaming Frog (free up to 500 URLs), Sitebulb, Ahrefs Site Audit, or Semrush and filter by response code 404. This finds broken internal links across your whole site in one pass.
- 3
Check your server access logs
Your web server (Apache/nginx) logs every request and its status code. Filtering the logs for '404' reveals real 404s that actual visitors and bots hit — including URLs no crawler would discover, like old external links.
- 4
Monitor 404s in real time
Crawls and Search Console are snapshots. Redirect Mapper logs every 404 a real visitor hits the moment it happens — with the referring URL — so you catch newly broken links continuously instead of once a month.
- 5
Fix each 404 with the right redirect
For each broken URL, add a 301 redirect to the closest live page (not the homepage), or let automated matching resolve it. Then re-check Search Console to confirm the errors clear.
Automate 404 recovery with Redirect Mapper
Instead of periodically hunting for broken links, Redirect Mapper turns finding and fixing into one step: its snippet detects every 404 in real time, redirects the visitor to the closest live page automatically, and logs each broken URL and referrer to your dashboard for export.
Frequently asked questions
Google Search Console is the best free option for finding 404s that affect your search presence — its Pages report lists 'Not found (404)' URLs. For crawling internal links, Screaming Frog is free up to 500 URLs. Combine both for broad coverage.