Calculating the First Business Day of the Month

Dan is setting up a worksheet for use in his company and needs a way to calculate the first business day of a calendar month. He knows how to calculate the first day of a month, but that day could possibly fall on a weekend or on a holiday.

The easiest way to calculate the first weekday of a given month is to use the WORKDAY function, in this way:

=WORKDAY(EOMONTH(A1,-1), 1)

This formula finds the first weekday of the month of whatever date is in cell A1. The EOMONTH function returns the last day of the month prior to the date in cell A1, and then the WORKDAY function returns the first weekday in the following month.

The function is put together like this (using EOMONTH) because WORKDAY is a bit quirky; it assumes that the first parameter is a valid workday. This means that it doesn't check whether the date used in the parameter falls in the Monday through Friday work week. By forcing the parameter to be a day before the month in which you want to determine the first workday and setting the second parameter to 1, the function returns the first actual weekday for the desired month.

The WORKDAY function also allows you to optionally specify that holidays should be taken into account. The easiest way to do this is to set up a list of holiday dates, in a cell range, and then name that range. (How you name a range is discussed in other issues of ExcelTips.) If you give the range a name such as MyHolidays, then you can use the following version of the formula:

=WORKDAY(EOMONTH(A1,-1), 1, MyHolidays)

Here's a neat trick if you want to calculate the beginning workday for any given month in a year. Assume that cell A1 contains a year, such as 2020, and that cell A2 contains a month number, 1 through 12, representing the month for which you want the beginning workday. You can then use this formula to get the desired date:

=WORKDAY(DATE(A1,A2,0), 1, MyHolidays)

The way the DATE function is used in this formula returns the last day of the month prior to the month and year specified in cells A2 and A1. The second parameter for WORKDAY (1) then moves forward to the next workday. MyHolidays (as before) accounts for any holidays that may occur in that month.

The WORKDAY function works just fine for dates within the US, but it gets a bit dicier if you need workdays in other countries. In that case, try using the WORKDAY.INTL function (introduced starting with Excel 2010) to see if it will do the trick for you. It is much more flexible in how it allows the designation of weekends and holidays.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (10201) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, and Excel in Microsoft 365. You can find a version of this tip for the older menu interface of Excel here: Calculating the First Business Day of the Month.