Metrics · Product · Retention · Weekly · minutes · Updated 2026-07-21

What is Average Session Length?

Short answer: The average duration of a single user session within the product.

Definition

The average duration of a single user session within the product.

Formula

Sum of session durations / Number of sessions

How to measure

Track session start and end timestamps for each user visit and average the duration across all sessions in the period.

Why track it

Session length is a useful engagement depth signal, though it should be read alongside frequency, since a longer session isn't always a better outcome.

Example

A learning app's average session length grows from 4 to 11 minutes after adding progress tracking that encourages users to finish a full lesson.

FAQ

What is Average Session Length?
The average duration of a single user session within the product.
How do you calculate Average Session Length?
Sum of session durations / Number of sessions
Why track Average Session Length?
Session length is a useful engagement depth signal, though it should be read alongside frequency, since a longer session isn't always a better outcome.
What is Average Session Length? Definition, formula, and growth use · Cofounderbase