Returns the date of the last day of a month which falls Months away from the Start date.
EOMONTH (Start date; Months)
StartDate is a date (the starting point of the calculation).
Months: the number of months before (negative) or after (positive) the Start Date.
What is the last day of the month that falls 6 months after September 14 2001?
=EOMONTH(DATE(2001;9;14);6) returns the serial number 37346. Formatted as a date, this is 2002-03-31.
=EOMONTH("2001-09-14";6) works as well. If you specify the date directly, we recommend using the standard ISO 8601 format because this should be independent of your selected locale settings.