Set the length of task duration

You can change a task's duration at any time to reflect the actual amount of time it needs.

  1. Click View > Gantt Chart.
  2. In the Duration column for the task, type the duration in minutes (m), hours (h), days (d), weeks (w), or months (mo).
  3. If the new duration is an estimate, type a question mark (?) after it.
  4. Press Enter.

Be careful about changing a duration by using the Start and Finish columns, especially for linked tasks or automatically scheduled tasks. Your changes might conflict with the task dependencies or task constraints Project is tracking, which can throw a carefully constructed schedule off track.

Change a summary task duration
Is not possible to change the duration of a summary task.

On the Gantt Chart, a summary task bar always shows the summary task duration (black line) and the sum of the durations of its subtasks (blue bar), like in the picture below. You can see the difference between the two at a glance.