Calculating Business Days

In performing calculations with Excel, it is often helpful to know how many days there are between two dates. Excel makes this easy--you just subtract the earlier date from the latter.

In a business environment, however, you may not want to know just the number of days--you probably want to know the number of business days between two dates. In other words, how many workdays are there between two dates?

Believe it or not, Excel makes it almost as easy to calculate business days as it is to calculate regular days. All you need to do is use the NETWORKDAYS worksheet function. This function is not intrinsic to Excel; it is part of the Analysis ToolPak. (You make sure this add-in is loaded by choosing Add-Ins from the Tools menu.)

Let's suppose for a moment that you had two dates: one in A3 and the other in A4. The date in A3 is your starting date and the date in A4 is the ending date. To calculate the work days between the two dates, you could use the following formula:

=NETWORKDAYS(A3,A4)

This returns a count of all the days between the two dates, not counting weekends. You should note that the function returns the number of full days. Thus, if your starting date was Sept. 4 and your ending date was Sept. 5, the function would return a value of 2. (Provided neither day was a weekend day.)

If you want to account for holidays, the easiest way is to enter your standard holidays in a range of cells, and then define a name for that range. (I always like the terribly obvious name of "Holidays.") You can then alter the NETWORKDAYS formula in this manner:

=NETWORKDAYS(A3,A4,Holidays)