How Broken Links Affect SEO and How to Detect Them

Broken links (404 errors) are a quiet SEO problem — they rarely drop your rankings overnight, but ignore them and your site gradually loses trust with search engines and users.

Why broken links hurt SEO

• They waste crawl budget — Googlebot cannot reach the pages you actually want indexed
• They signal an unmaintained site
• Internal PageRank flowing through the link is lost
• Users bounce, which feeds back into ranking signals

Not all 404s are the same

• Internal broken links: typos or missed URL migrations
• External broken links: third-party sites that went offline
• Asset 404s: missing images / CSS / JS
• Redirect loops or chains: technically 2xx, still penalised

How to detect them

1. Use a crawler

Fastest and most complete. A tool like sitemora runs a full site crawl from a single URL and lists every 404 with the page that points to it.

2. Google Search Console

Under Indexing → Pages. It only shows pages Google has already tried to crawl, so fresh broken links may not show up yet.

3. Access log analysis

Server logs tell you which 404 URLs users are actually hitting — perfect for prioritising fixes.

How to fix them

1. Internal broken links: fix the HTML, or do a CMS-level bulk replace
2. Deleted pages: 301 to the closest replacement, or return 410 Gone when nothing fits
3. External broken links: remove, or swap in an archive.org link
4. Asset 404s: remove the reference or correct the path

It is tempting to 301 every deleted page, but if nothing on the new site maps to it, an honest 404 or 410 is cleaner than a misleading redirect.

Make checks recurring

• Run a site-wide crawl at least once a month
• Spike of 20+ new 404s → fix immediately
• Any 404 landing on your top page or a main category — same-day fix

sitemora's Business plan schedules monthly crawls and diffs them automatically so the team can see at a glance whether broken links are trending up.