Microsoft Project - The Important Difference Between Working Time and Elapsed Time

What is the difference between actual elapsed time and Project time - and why is this important in Project plans? Project time is all about working time and therefore weekdays and holidays don't count.

For example, using MS project to manage the timeline for a construction project - if you've poured the concrete for foundations on Friday so that it can set over the weekend 3 days setting time in MS Project means that construction work is not planned to resume until Wednesday, not the Monday when the concrete will be ready. Why are days being wasted?

Project time is always working time

That's because you set the duration to 3 days and as far as Project is concerned, that's 3 working days. You should have set the duration to 3 elapsed days so that you can crack on with the next phase as soon as the concrete has set.

Elapsed time includes non-working time

Every task needs a duration. The duration is the length of working time from start to finish that it will take to complete the task. Project sets the duration of Auto Scheduled tasks to one day unless you fill in a different value. The duration of Manually Scheduled tasks is calculated automatically from their start and finish dates, although you can override this by entering the duration and Project will calculate the finish date.

Valid Time and Date Units for Microsoft Project

You can enter durations in minutes (m), hours (h), days (d), weeks (w) or months (mo). Type the number followed by the abbreviation for the unit you want to use. For example, type 3d for 3 days or 6h for 6 hours. This uses time as defined by the Project Calendar, to use real time you should include an e prefix to any of the time units. For example, type 3ed for 3 elapsed days or 2emo for 2 elapsed months.

When you type durations like 3ed, 2w or 8h Project replaces the abbreviated units with more complete text. Type-in "d" and Project substitutes “days.” As you select a Duration cell, spinners appear so that you can click to increase or decrease the duration by one unit.