Like everything else in life, each task in your project will take a certain amount of time to complete (unless it’s a milestone). That certain amount of time is called the task duration. By including each task’s duration in your project plan, you get some sense of how long the project will take. Besides, Microsoft Project can’t calculate a schedule accurately if it doesn’t have accurate duration estimates from you. So you’re going to need some way to estimate task duration. You can approach this in several ways:
In Microsoft Project, a task’s duration does not include any nonworking time, such as weekends and holidays. So, for example, a 4-day task scheduled to begin on a Thursday will occur on Thursday, Friday, Monday, and Tuesday.
If you want to schedule a task over a continuous period of time, including nonworking time, you can specify an elapsed duration. Using elapsed duration, a 4-day task that begins on a Thursday will occur on Thursday, Friday, Saturday, and Sunday. For example, use elapsed duration to indicate the time required for a painted wall to dry. If the wall was painted on Friday and it took 2 days to dry, the elapsed duration would span 3 days, beginning on Friday and ending on Sunday.