Formula needed to calculate working days in specified month between two dates

Are your normal workdays Monday thru Friday? Will you need to exclude any holiday dates?

Why can't you just define the period as May 1 2013 thru May 17 2013?

If you have start date in A2 and end date in B2 then list the 1st of each month in C1 across and then use this formula in C2 copied across for the number of workdays in each month

=MAX(0,NETWORKDAYS(MAX($A2,C$1),MIN($B2,EOMONTH(C$1,0))))

You can format Row 1 as mmm-yyyy or similar

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