How to Change a Task Duration in Microsoft Project

Scheduling within Microsoft Project will only be as good as the information put into the database. It is important to select the proper duration units, and to know when the duration is an estimate. In order to improve on estimates, of vital importance in understanding the past and what has already transpired. This is the key to improving the accuracy of the project schedule. Document the information as you work through the project and as tasks are completed. This information will assist you in understanding the true durations, and the problems and challenges that can occur. If you could do things differently next time, what would the changes be?. This information is called lessons learned, and will provide key information for all future projects and new tasks that are created. Using realistic task durations is vital to project success. By using the lessons learned, you have valuable insight to areas that need adjusting.

Automatic and Manual Project Scheduling
Automatically scheduled tasks are created in Microsoft Project with an estimated duration of one day.
This is a default setting which can be changed to reflect the actual duration of the task.

There are two Microsoft Project settings used for scheduling tasks. Manually scheduled tasks are the default, meaning that new tasks must be manually scheduled and do not have any default duration preset. Automatically scheduled tasks setting allows for all new tasks to show default duration.

To change the scheduling setting to automatically scheduled:
1.    In the Tasks tab, in the Tasks group, click Auto Schedule.

Another way to switch between the Manual and Auto selection is to click on the bottom of the project window, just above the task bar. A box will appear in which you can select Automatic or Manual scheduling.

Switching between Manual and Automatic scheduling

There are several parts of a task that can be changed:

Changing the Default Units
1.    On the File tab, click Options.
2.    In the Project Options box, click Schedule.
3.    In the Duration is entered in box, enter the selected duration unit.

Changing the Default Units

Changing the Duration of a Task
Durations can depend on the experience of the person to whom the task is assigned. A very experienced worker can accomplish the task usually in less time than an inexperienced worker.

1.    Type the duration in minutes(m), hours(h), days(d) weeks(w), or months(mo) in the Duration column of the task.
2.    If the duration is an estimate, then type a (?) after it
3.    ENTER

Entering the Duration of a task

Changing the Duration of a Summary Task
Follow the same process as outlined for Changing the Duration of a Task. A Summary Task should show the total duration of the subtasks associated to it. If you are changing the duration of a Summary Task and the duration is different from the total duration of the subtasks, the system will show the discrepancy by showing the difference in Red in the Chart portion of the view.

Simon C

Chris “Simon” Calder was working as a Project Manager in IT for one of Los Angeles’ most prestigious cultural institutions, LACMA. He taught himself to use Microsoft Project from a giant textbook and hated every moment of it. Online learning was in its infancy then, but he spotted an opportunity and made an online MS Project course - the rest, as they say, is history!