Specifying duration in Microsoft Project - working with elapsed time

One of the errors newcomers to Project do is that they do not grasp the difference between Work and Duration. Not so strange, since only the Duration column is visible in the Gantt chart. But Duration is the calendar time between a task starts and the time it finishes. Work is the man hours spent on the task. You could say that work affects the costs of the project and duration the length of the project. On my post on task types you can see how these fields works together. But back to Duration.

Duration is the calendar time and when you set this on a task you type in a number and a unit. The units can be minutes, hours, days, weeks and months. How you print in the unit depends on which cultural version of project you use. For example you can type in t for hours in the Swedish Project but you need to print h in the English. Also, remember that m is minutes and yoy need to type something longer (for example mon in the English project). Be sure to check the metrics used in your version!

If you set the Duration of a task to 7 you can see that there will not be 7 calendar days between start and finish. There will probably be 9. Why? Well, by days Project means working days. If you go to Tools-->Change Working time you can see that Saturdays and Sundays are non working days. This means that the tasks will proceed during these days but no work will take place. If other days are marked as non working days in the calendar, they too will be skipped. And remember that if you mark days as non working for a specific resource, they will be skipped on the tasks where the resource is set.

But then there are tasks which work will commence independant on if it's working time. For example, I want to give a customer 14 days to think something over. Or concrete dries in a specific time. What I can do is that I can add a e in the English project before the metric. For example 14 ed. Remember that the e is dependant on which version of Project you are using: in the Swedish version you type in a t instead. The e stands for Elapsed and means that work will take place 24 hours a day, 7 days a week.