Page depth (or pages per session) measures how many pages a visitor views before leaving your site. A page depth of 3.2 means the average visitor views about 3 pages. It's a standard engagement metric in every analytics platform, but it's one of the most misinterpreted.
High page depth on a content site? Great — visitors are exploring, consuming, staying. High page depth on a conversion-focused site? Possibly terrible. If someone visits your homepage, then your features page, then your pricing page, then your FAQ, then your about page, then leaves — that's a page depth of 5 and zero conversions. They were hunting for an answer they never found.
Interpreting page depth correctly
For dedicated landing pages, page depth should be close to 1-2. The visitor arrives, gets what they need, and converts (or leaves). If your landing page has a page depth of 3+, visitors are clicking away from your landing page to other parts of your site — which usually means the landing page didn't answer their questions or build enough confidence.
For full websites, track page depth alongside conversion rate. If increasing page depth doesn't increase conversions, your visitors aren't exploring — they're lost. The fix isn't adding more pages; it's putting the right information on fewer pages. The best-performing sites I've analyzed tend to have moderate page depth (2-4) with high conversion rates, not deep page depth with low conversions.