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 Remaining Duration field shows the amount of time required to complete the unfinished portion of a task.
How Calculated If you type a value in the Actual Duration field or % Complete field, remaining duration is calculated using the following formulas:
Remaining Duration = Duration - Actual Duration
Remaining Duration = Duration - (Duration * Percent Complete)
If you type a value in the Remaining Duration field, Microsoft Office Project calculates a new duration and completion percentage. If you increase or decrease remaining duration, Project changes duration to match the sum of the remaining duration and actual duration and leaves the actual duration unchanged.
Best Uses Add the Remaining Duration field to a task sheet when you want to edit, display, or filter for remaining duration information. Edit the Remaining Duration field for the task when you need to increase or reduce the remaining portion of the task.
Example The "Write proposal" task is scheduled for a five-day duration. To date, two and a half days have passed. Chris has just informed you that the task will need another week before it's completed. You add the Remaining Duration field to the Task Sheet view, and edit the field to add five more days of Remaining Duration for this task.
Remarks Because typing a value in the Remaining Duration, Actual Duration, or % Complete field automatically recalculates the other fields, you should enter a value in only one of these fields for a task.