Author: Oscar Cronquist Article last updated on April 12, 2018

The EOMONTH function returns an Excel date for the last day of a given month using a number and a start date.

Use EOMONTH to calculate maturity dates or due dates that fall on the last day of the month.

Formula in cell C3:

=EOMONTH(B3)

Excel Function Syntax

EOMONTH(start_date, months)

Arguments

start_date Required. A date that represents the starting date. Don't use text dates, use Excel dates, see comments below.
months Required. A number that determines how many months before or after the start date. A negative value returns a date earlier than the start_date.

Comments

Excel dates are actually numbers formatted as dates. January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900.

The DATE function allows you to return an Excel date in the EOMONTH function. =EOMONTH(DATE(2008,1,1),2) returns 3/31/2008.