Duration
Scheduling Terms
Reviewed by forProject Technology - updated Sep 2026
Quick definition: Duration is the number of work periods — usually working days — that a task spans on its Working Calendar, not counting non-working periods such as weekends and holidays. Duration is not effort: a one-day task might involve one labor hour or a hundred.
Duration counts only working periods, so it isn't the same as elapsed calendar time. It is most often expressed in working days, but any time unit can be used, as long as it counts working periods on the task's Working Calendar.
What this means for you
Getting Duration right is fundamental to building a credible schedule, since it drives calculated dates, Float, and ultimately the Critical Path. Confusing Duration with labor effort is a common scheduling mistake that can throw off an entire schedule.
Also known as
N/A
Used in
Critical Path Method calculations; Duration Percent Complete
FAQ
Is Duration the same as the amount of work required for a task?
No. Duration is working time measured on a Working Calendar, while effort is the amount of labor required, measured in labor hours, for example. A task can have a long Duration with little effort, or the reverse.
What Working Calendar is Duration measured against?
A Working Calendar defined for the project, task, or resource, which separates working periods from non-working periods such as weekends and holidays.
Definition maintained by forProject Technology.
© 2026 forProject Technology, Inc.
© 2026 forProject Technology, Inc.
