By default, task durations are calculated automatically, based on each task's work estimate, the calendar and the Work Estimates Configuration.
Manually Adjusting Duration
To adjust a task's duration:
- Edit the task's work estimate fields, or
- Drag the right side of the task bar. (Note: the work estimate field must be added to the appropriate issue screen.)
Dragging the right side of a task bar will cause the task's work to be updated and its duration to be recalculated.
If you have both Start and End dates defined, work estimates will be ignored and resizing the task bar will only affect the Finish Date.