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Understanding the Nonworking Time Calendar in Microsoft Project

Background

When you need to change the Project Calendar to a base calendar other than the Standard calendar in Microsoft Project, don’t forget to change the Nonworking Time Calendar as well. At this point, you are probably asking yourself, “What is the Nonworking Time Calendar? And where do I set this calendar anyway?”

At the top level in Microsoft Project, there are two calendars that a user can set for the project. They are known as the Project Calendar and the Nonworking Time Calendar. These calendars function as follows:

  • Microsoft Project uses the Project Calendar to calculate the initial schedule each task in the project prior to assigning resources to tasks.
  • Microsoft Project uses the Nonworking Time Calendar to display nonworking time, such as weekends and company holidays, as gray shaded vertical bands in the Gantt Chart screen in Gantt-based views such as the Gantt Chart and Tracking Gantt views.

By default, Microsoft Project sets the Standard calendar as both the Project Calendar and the Nonworking Time Calendar in every new project you create. But what if you need to use a calendar other than the Standard calendar to schedule your project?

For example, I created a custom base calendar named US Federal Holidays in my project, as shown in Figure 1. In the Change Working Time dialog, notice that you can see US federal holidays, such as Martin Luther King Day, specified as nonworking time.

Figure 1: US Federal Holidays calendar created

Figure 1: US Federal Holidays calendar created

I want to use the US Federal Holidays calendar instead of the Standard calendar to schedule my project. How do I accomplish this? I need to change the calendar twice using two different dialogs in Microsoft Project. Let me show you how to do this.

Changing the Project Calendar

Remember that Microsoft Project uses the Project Calendar to determine the initial schedule of every task in the project prior to assigning resources to tasks. To change the Project Calendar in a project, complete the following steps:

  1. Click the Project tab to display the Project ribbon.
  2. In the Properties section of the Project ribbon, click the Project Information button.
  3. In the Project Information dialog, click the Calendar pick list and select the alternate calendar you want to use. In my scenario, I need to select the US Federal Holidays calendar, such as shown in Figure 2.
Figure 2: Change the Project Calendar

Figure 2: Change the Project Calendar

  • In the Change Working Time dialog, click the OK button.

At this point, Microsoft Project has rescheduled every task in the project to use the working schedule shown on the US Federal Holidays calendar, but the software does not display those holidays in the Gantt Chart screen. For example, the Veterans Day federal holiday is Friday, November 11, 2022. However, notice in Figure 3 that this holiday is not shown as nonworking time using a gray shaded vertical band in the Gantt Chart screen. This is why I also need to set the US Federal Holidays calendar as the Nonworking Time Calendar for the project.

Figure 3: Columbus Day not shown in the Gantt Chart Screen

Figure 3: Columbus Day not shown in the Gantt Chart Screen

Changing the Nonworking Time Calendar

To set the Nonworking Time Calendar in a project, you must use the Timescale dialog with the Non-working time tab selected. There are two methods I like to use to display this dialog:

  • Double-click the Timescale bar at the top of the Gantt Chart screen and then select the Non-working time tab.
  • Double-click anywhere in a gray shaded vertical band in the Gantt Chart screen (my personal favorite method).

On the Non-working time page of the Timescale dialog, click the Calendar pick list and select the alternate calendar that you selected as the Project Calendar. Notice in Figure 4 that I am selecting the US Federal Holidays calendar in the Calendar pick list. Notice also that Microsoft Project identifies this calendar as the Project Calendar by appending (Project Calendar) at the end of the calendar name.

Figure 4: Select the Nonworking Time calendar

Figure 4: Select the Nonworking Time calendar

Click the OK button in the Timescale dialog to apply the selected calendar as the Nonworking Time Calendar for the project. Notice in Figure 5 that the Gantt Chart screen now displays a gray shaded vertical band for the Veterans Day holiday on Friday, November 11, 2022.

Figure 5: Gray shaded band shown for Veterans Day

Figure 5: Gray shaded band shown for Veterans Day

Remember that if you need to change the Project Calendar to any base calendar other than the Standard calendar, then you also need to specify the same calendar as the Nonworking Time Calendar as well. Doing so will spare you the confusion of a Gantt Chart screen that may not match the project schedule.

Coming Up…

In my next blog post article, I will show you an advanced technique for using the Nonworking Time Calendar to troubleshoot scheduling issues.

Other Microsoft Project Resources

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Written by Dale Howard

Dale Howard is currently a Senior PPM Consultant with Arch Systems, Inc. His hair and beard have turned white because of using Microsoft’s project management tools for more than 20 years. Dale started his career using Microsoft Project 4.0 for Windows 95 and began using Microsoft’s PPM tools when they introduced Project Central in 2000. Dale is the co-author of 23 books in Microsoft Project, Project Server, and Project Online. He is currently one 0f 26 Microsoft Project MVPs in the entire world and one of only 4 Project MVPs in the United states.

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