# duration The cumulative time in seconds that an activity has been active. ``` var duration: TimeInterval { get } ``` ## Discussion When you create a new activity to represent a new attempt at a task by calling the [`createNewActivity()`](/documentation/ClassKit/CLSContext/createNewActivity()) method, the duration initializes to zero. After calling the [`start()`](/documentation/ClassKit/CLSActivity/start()) method, it begins counting seconds. When you call the [`stop()`](/documentation/ClassKit/CLSActivity/stop()) method, the duration counter stops. It resumes counting (without resetting) if you make a new call to the [`start()`](/documentation/ClassKit/CLSActivity/start()) method, enabling you to effectively pause an activity. However, when you create a new activity, the duration of the previous activity stops permanently and is no longer accessible to your app. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)