• ### Question

• Hi,

I have two task under one summary task that are each only one day in duration (the one starts and finishes on 3 March, the other starts on 7 April) but the summary task displays a duration of 25 days. How do I make the summary task only count duration as 2 days and not 25 days?

Thanks, Jaco

Wednesday, February 26, 2014 7:53 AM

• Hi Jaco,

Well, the duration between the two tasks is 25 days, and therefore the summary task is correct.  However, you can insert the Work column, and assign 1 day of work to each task (by default this will display in hours, but under the Options | Advanced options you can set this to days).  This will then provide a summary of 2 days WORK on the summary task.

It's worth understanding the difference between work and duration!

Ben Howard [MVP] | web | blog | book

Wednesday, February 26, 2014 8:07 AM
• Jaco,

Ben is right, when using Project it is necessary to understand the difference between duration and work, so let me try and give you a quick study.

Duration is simply a span of time. For a summary task, it is the working time from the start of the first subtask through the finish of the last subtask. Duration accomplishes nothing. Duration is not additive.

Work on the other hand is the effort needed by one or more resources to actually accomplish the task. Work is additive. If a single resource is assigned 100% to a task then the duration and work will be the same. I

In your case, if a single resource is assigned to the first task, the duration of that task will be 1 day and the work content will be 8 hours. For the second task, the duration of that task will be 2 days with a work content of 16 hours. The total duration of both tasks, given the start and finish dates you indicate (assuming a normal standard calendar) is actually 27 days but the total work content of both tasks is 24 hours.

Hope this helps.

John

Wednesday, February 26, 2014 3:56 PM

### All replies

• Hi Jaco,

Well, the duration between the two tasks is 25 days, and therefore the summary task is correct.  However, you can insert the Work column, and assign 1 day of work to each task (by default this will display in hours, but under the Options | Advanced options you can set this to days).  This will then provide a summary of 2 days WORK on the summary task.

It's worth understanding the difference between work and duration!

Ben Howard [MVP] | web | blog | book

Wednesday, February 26, 2014 8:07 AM
• Jaco,

Ben is right, when using Project it is necessary to understand the difference between duration and work, so let me try and give you a quick study.

Duration is simply a span of time. For a summary task, it is the working time from the start of the first subtask through the finish of the last subtask. Duration accomplishes nothing. Duration is not additive.

Work on the other hand is the effort needed by one or more resources to actually accomplish the task. Work is additive. If a single resource is assigned 100% to a task then the duration and work will be the same. I

In your case, if a single resource is assigned to the first task, the duration of that task will be 1 day and the work content will be 8 hours. For the second task, the duration of that task will be 2 days with a work content of 16 hours. The total duration of both tasks, given the start and finish dates you indicate (assuming a normal standard calendar) is actually 27 days but the total work content of both tasks is 24 hours.

Hope this helps.

John

Wednesday, February 26, 2014 3:56 PM
• Thank you very much Ben!
Friday, February 28, 2014 7:46 AM
• Thank you John, understood.
Friday, February 28, 2014 7:46 AM
• Jaco,

You're welcome and thanks for the feedback.

John

Friday, February 28, 2014 3:34 PM