Hi,

In my previous post I have explained how to use the Project Calendar, and how to make an exception (Vacation, New Year etc.). But what if you have different working times over the period. For example, our “Wedding” Project has working time from Monday to Friday from 08:00 to 12:00 and from 13:00 to 17:00. And it will start at 01.08.2011. Suppose that we want to keep that working time from 01.08.2011 to 15.08.2011, and then from 16.08.2011 to 31.08.2011 we want to work from 16:00 to 20:00, and then from 01.09.2011 go back to old working time.

I’ll show you how to do it in my “Wedding” Project, but this is the Example, so I will delete those working times later, because I will not need them in the future

Here it is:

Notice that you CAN NOT change the Default row.

Now be very concentrate. If you read my previous post you know that I made an exception in the Project Calendar for my Vacation time:

I will now, just for example, put a Auto Scheduled Task which will start (by default) at 01.08.2011 (Project start date), and will have 20 days Duration. I will get:

WOW! I have task with 20 days Duration, it will start at 01.08.2011 and it will be finished at 08.09.2011????

Well, now you understand why is SO IMPOTRANT to understand MS PROJECT 2010 calendars. Here is the explanation.

First, when I told that my task will have a 20 days duration, MS PROJECT 2010 has converted 20 days into 20 days X 8 hours per day = 160 hours.

We know that one day has 8 hours from here: On the File Tab click Options, and then Schedule and you will see:

The Task will start at 01.08.2011 (The Project Start date). OK. We need 160 hours. And we will get them:

• From 01.08.2011  (Monday) to 05.08.2011 (Friday) = 5 days X 8 hours / day  = 40 hours
• From 08.08.2011 (Monday) to 12.08.2011 (Friday) = 5 days X 8 hours / day = 40 hours
• From 15.08.2011 (Monday) to 21.08.2011 (Sunday), there are no activities on the Task because of Calendar Exception (Vacation, remember???)
• From 22.08.2011 (Monday) to 26.08.2011 (Friday) = 5 days X 4 hours / day = 20 hours. WHY? Because working time from 16.08.2011 to 31.08.2011 is from 16:00 to 20:00 and it means only 4 hours per day
• From 29.08.2011 (Monday) to 31.08.2011 (Wednesday) = 3 days X 4 hours / day = 12 hours. WHY? Read one sentence above
• From 01.09.2011 (Thursday) to 02.09.2011 (Friday) = 2 days X 8 hours / day = 16 hours. WHY? We are on the old working time!
• From 05.09.2011 (Monday) to 08.09.2011 (Thursday) = 4 days X 8 hours / day = 32 hours. WHY? You know very well why

And it makes 40+40+20+12+16+32= 160 hours!

What will happens if I remove this working week from 16.08.2011 to 31.08.2011 from my Project Calendar?

I will get:

The Finish date is 02.09.2011.

• From 01.08.2011 (Monday) to 05.08.2011 (Friday) = 5 days X 8 hours / day = 40 hours
• From 08.08.2011 (Monday) to 12.08.2011 (Friday) = 5 days X 8 hours / day = 40 hours
• From 15.08.2011 (Monday) to 21.08.2011 (Sunday), there are no activities on the Task because of Calendar Exception (Vacation, remember???)
• From 22.08.2011 (Monday) to 26.08.2011 (Friday) = 5 days X 8 hours / day = 40 hours. WHY? Because I remove working time from 16.08.2011 to 31.08.2011 which was from 16:00 to 20:00 and only 4 hours per day
• From 29.08.2011 (Monday) to 02.09.2011 (Friday) = 5 days X 8 hours / day = 40 hours. WHY? Read one sentence above

And it makes 40+40+40+40= 160 hours!

Now, I will remove my Vacation from exception from MS PROJECT 2010 Calendar:

and I will get:

The Finish date is 26.08.2011.

• From 01.08.2011 (Monday) to 05.08.2011 (Friday) = 5 days X 8 hours / day = 40 hours
• From 08.08.2011 (Monday) to 12.08.2011 (Friday) = 5 days X 8 hours / day = 40 hours
• From 15.08.2011 (Monday) to 19.08.2011 (Friday) = 5 days X 8 hours / day = 40 hours
• From 22.08.2011 (Monday) to 26.08.2011 (Friday) = 5 days X 8 hours / day = 40 hours

And it makes 40+40+40+40= 160 hours, again.

At the end of this post, do I have to emphasize that you should be EXTREMLY CAREFUL when you are changing calendars in MS PROJECT 2010, or working time???

If you think that this is complicated you are hitting the target. BUT, the real pain begins with Resource calendars, and the Task Calendars.

In my next post I will start with them! For the example I will leave Exception for the Vacation and 4 hours working days from 16.08.2011 to 31.08.2011, to make the whole thing more complicated.

Until my next post,

Best Regards!