Data Type Duration (duration field: A type of field whose content is expressed as a duration of time. Examples include the Work, Duration, and Delay fields. A duration field includes the duration unit, such as hour, day, or week.)
Entry Type Calculated or entered (calculated or entered field: A field in which the value is determined by Project based on information in other fields. Information that you enter in the field yourself overrides calculated values.)
Description The Duration field is the total span of active working time for a task. This is generally the amount of working time from the start to the finish of a task.
How Calculated Project calculates the duration of a task by counting the amount of active working time between the scheduled start and end of the task. This is generally the time from task start to finish, not counting time between split tasks (split task: A task whose schedule is interrupted. For example, a two-day task that does not require contiguous work might be split so that the first day of work is scheduled for Monday, and the second day is scheduled for Thursday.) or nonworking time.
Best Uses Enter the duration for tasks when you create the tasks. The Duration field is one of the major elements for Project scheduling calculations. It is the span of time shown by the Gantt bars on the Gantt Chart.
Example Chris is scheduled to work on the "Write proposal" task on Wednesday, Thursday, and Friday. Jamie is scheduled to work on the "Write proposal" task on Wednesday and Thursday. Sean is scheduled to work on the "Write proposal" task on the following Monday and Tuesday. The working span of the "Write proposal" task, and therefore its duration, is five days (Wednesday, Thursday, Friday, Monday, and Tuesday).
Remarks In an automatically scheduled task (automatically scheduled task: This type of task is scheduled using Project's scheduling engine, taking into account task constraints, dependencies, project calendars, and resource calendars.), the default for new tasks is estimated as 1 day (1d?). The question mark indicates that the duration is an estimate. Add a question mark to any duration estimate. Remove the question mark to indicate a committed duration. You can filter or sort by estimated durations.
Note For Project 2007 and earlier versions, all tasks are automatically scheduled.
You can change the one-day default value, as well as express the durations of new tasks in units other than days, in the Project Options dialog box.
In an automatically scheduled task, Project uses the duration you enter to calculate start and finish dates, along with task dependencies (task dependencies: A relationship between two linked tasks; linked by a dependency between their finish and start dates. There are four kinds of task dependencies: Finish-to-start [FS], Start-to-start [SS], Finish-to-finish [FF], and Start-to-finish [SF].), constraints (constraint: A restriction set on the start or finish date of a task. You can specify that a task must start on or finish no later than a particular date. Constraints can be flexible [not tied to a specific date] or inflexible [tied to a specific date].), calendars, and other scheduling factors.