Using Calendars in Microsoft Project 2010
Part two of a three-part series of blogs

You can't do much in Microsoft Project without understanding how calendars work. Calendars control when work is allowed to happen, so it's important to set them up properly before you start planning your tasks. This blog teaches you how.

  1. Using Calendars in Microsoft Project 2010
  2. Creating Exceptions in Microsoft Project 2010 (this blog)
  3. Creating New Calendars in Microsoft Project 2010

Posted by Andrew Gould on 02 March 2012

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Creating Exceptions in Microsoft Project 2010

Microsoft Project provides you with three built-in calendars to choose from, but you'll rarely find that they match the requirements of your own working hours.  This part of the series explains how to make changes to an existing calendar.

Creating Exceptions

The easiest type of change to make to a calendar is to create an exception.  You can use an exception to model an irregular change to the normal pattern of working hours.  Usually, this is done to change a working day into a non-working day.  National holidays are good examples of exceptions and here's how to create one:

  1. From the ribbon select: Project -> Change Working Time.
  2. Choose the calendar to which you want to add an exception.
  3. Select the day or days you want to add the exception to.

Somehow the concept of hereditary monarchy is alive and well in the UK, even in the 21st century!

  1. In the table, type in a name for the exception and press Enter.
  2. The dates of the exception will appear here.

The end result should be that the selected day becomes a non-working day, as shown below:

Exception created

The exception day will be highlighted in the calendar.

When you have finished creating exceptions, click OK at the bottom of the dialog box.

According to the Microsoft website, they have tested adding over 15,000 exceptions to a single calendar.  Hopefully you won't need anywhere near this number!

Exceptions and Non-Working Time

When you add an exception to a calendar it is most commonly done to change a working day into a non-working day.  As the name suggests, non-working time is time during which no tasks may occur.  The diagram below shows what effect this has on tasks.

Effect of non-working time

The miserable and unpatriotic person in charge of this project is trying to continue working during the Queen's celebrations.  Unfortunately for him the non-working time in the calendar doesn't allow tasks to occur during this time.  This means that the two-day task he begins on Monday won't finish until the end of Wednesday.

Editing the Details of an Exception

When you first create an exception, the days that you have selected will be set to a non-working day.  It might be the case, however, that you simply want to change the hours of work for a day.  To do this you'll need to view the details of the exception:

  1. Select the exception you want to edit.
  2. Click the Details... button.
Viewing details

Click the button shown to edit the exception.

  1. Choose to edit the working times of the exception.
Editing exception

Here we're setting the day in question to only allow work between the hours of 8 and 12.

  1. Type in the new working hours you want to apply.  Here we've deleted the second row of working hours by clicking at the left-hand side of the table and pressing Delete on the keyboard.
  2. Click OK.

You can see the working times for the exception whenever you select the day in the calendar:

Edited exception

You can see the working times at the right-hand side of the dialog box when you select a day in the grid.

Recurring Exceptions

Some exceptions will happen on a regular basis, Christmas day for example, and it's useful to not have to create these exceptions multiple times.  You can create a recurring exception to handle this type of non-working time:

  1. Create an exception to handle the first occurrence of the event in a calendar.
New exception

Here we've created an exception for Christmas Day of this year.

  1. Select the exception in the table.
  2. Click Details...
  3. Choose whether the exception is a working or non-working day.
Christmas day

Christmas Day is a non-working day each year in the UK.

  1. Define the pattern of recurrence using these options.  Everything is fairly self-explanatory here - for our example we know that Christmas comes but once each year.
  2. Choose how long you would like the exception to recur.  Here we're only allowing Christmas to occur for the next ten years, after which time it will be cancelled.
  3. Click OK.

You'll now find that Christmas day is allowed to happen every year.  Hurray!

What's Next?

The next part of this series shows you how to create a new calendar and set up its standard pattern of working times.


  1. Using Calendars in Microsoft Project 2010
  2. Creating Exceptions in Microsoft Project 2010 (this blog)
  3. Creating New Calendars in Microsoft Project 2010
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