Fixed work, Fixed Duration, Fixed Units explained

In last blog we understood the task type and how they related, Please read same before continuing below and remember the formula !

Duration x Units = Work

Use Fixed Work when you know the amount of work, In this case you can change the duration to stretch out or compress the time you allow to get that fixed amount of work done. Changing work changes duration proportionately, but changing duration does not change work.

Suppose you set fixed-work task to have 40 hours of work. Duration is automatically set to 5 days (by default 8 hrs./day) . Now if you change the duration to 10 days , the work will still remain as 40 hrs (Fixed work) and task changes: from 8 hours/day (the default) to 4 hours/day (units changes).

Other hand for Fixed Duration task the Duration remains constant, for example you have fixed-duration task set to 5 days. Work will automatically be set to 40 hours (by default calculation). Now if you change the work to 20 days the task changes: from 8 hours/day (the default) to 4 hours/day.(units changes)
Use Fixed Duration when you think about a task in terms of how much time you want to allocate for it irrespective of work and units.

Use fixed-units, when you think of tasks interchangeably in terms of its work and the time allocated for it. That's generally because, when you do assign resources to the task, you expect they will work on the task a fixed number of hours (i.e. units) of their time each day. So, changing either the work or the duration will change the other one proportionally.

Below table is quick cheat sheet to remember  the relationship .

Quick Cheat : Relationship between Work, Unit and Duration

Setup Calendar

Even before you jump and start entering your task in project it is good idea to set up the project calendar, In fact it would be good practice to quickly setup the calendar as first thing in project.

Why setting the calendar is important? Because your schedule is depend on this and MS project automatically consider the off hours to reflect correct possible schedule.

To setup calendar, GO to Project Menu and click on Change working time button

Once you click on this Project will open “Change working time” window. 

Even though the first option on this window says “For Calendar” it has broad view. Ie. It refers how you work time and days. If you select the dropdown you will find three options.

24 Hours: Project assume that you are working in all three shifts 24 hours

Night Shift: Project assumes the project is executed in night shifts (12 hours X 6 days)

And lastly standard: means you work 8 to 5, 5 days a week.

You must manually maintain the leaves and working hour exceptions in this three calendar separately if you are using this calendar for any task or as resource calendar.

If you can see next to Standard calendar in bracket mentioned as project calendar, this is the default calendar used by MS project to calculate duration, this is the one we setup while we setup the project information.

Now let’s move to our scenario, we know that no one works on X-Mas and 1st of Jan every year. So we need to mark them as holidays so Project don’t schedule any task for this days.

To mark 1st Jan as holiday select 1st Jan in calendar and enter “New year” in Name column.

If your project is supposed to be executed for 10 years, you don’t need to manually select every 1st of January and mark this as non-working day, you can easily set the recurrence using recurrence.

To do so select the new entry row and click details, select the recurrence as “Yearly” and fill out the range using Start and End after or End by.

Similarly to mark multiple day as off (i.e. X-Mas off on 25th and 26th Dec) go to December month and select both dates and enter X-Mas in Exception Name column.

Setup currency, hours and other details….

As our scenario customer is from Europe region we need to change the currency to Euro then default USD.

To do so, click on File menu and then select options. In Project Options dialog box select “Display” in left hand selection.

Change the currency to EUR automatically respective symbol will change. You can also change the decimal places if you want.

If you are following different calendar due to your project requirement you can change the calendar type in calendar section. There are three types of calendar is supported by MS Project , Default Gregorian Calendar, Hijri Calendar and Thai Buddhist Calendar.

Other interesting option on this screen is to show Entry bar option.

When you select this option Project will show Entry bar above your Gantt view like Excel.

Other than above the Schedule Menu has many different options that can change the look and feel and how Microsoft project calculate hours.

For example: The Week start on field can change the way weeks are represented in MS Project.

By default project assumes the standard working timings in your project is from 8 am to 5 pm and working hours in day are 8 and in week 40. You can customize it to your need if needed but usually it is not changed except someone really interested in micro managing the project.

If you are more concerned about how the values shown in Project you can check advance tab. It has many options  that you can play with to change the look and feel and behave however we will touch base the option whenever needed thus we will not go in much details here.