# Session Duration

Session duration (also called time on site) is the total amount of time a visitor spends on your website in a single session. It is measured from the first pageview to the last interaction. Note that single-page sessions often have a calculated duration of zero because there is no subsequent event to mark the end of the session.

## Related terms

- [Session](/content/glossary/session/index.html)  
- [Bounce Rate](/content/glossary/bounce-rate/index.html)