The EDATE function takes a starting date and a number as its input. It then increments (or decrements) the date by the number of months that you specify. If the number of months that you provide has decimals, it is truncated instead of rounded so keep it as a whole number. Dates require special care when being used in formulas as they don't behave like regular numbers do in spreadsheets.
This formula can be useful due to the fact that not all months have the same number of days. Additionally, February has a different number of days depending on the year. The EDATE function accounts for all of these differences.
The EDATE function add or subtracts a given number of months to a given date.
=EDATE(start date,number of months)
start date- The starting date from which the calculation begins. Remember how dates work in formulas so that you know how to enter this date.
number of months- The number of the month by which to increase/decrease the starting month
Example 1 - Plain and Simple
A simple example of the EDATE function.
|=EDATE("5/17/2017",13)||Add 13 months to 5/17/2017||6/17/2018|
|=EDATE("5/17/2017",-2)||Subtract 2 months from 5/17/2017||3/17/2017|
The EDATE function can go forward and backward in time.
Example 2 - Knowing the number of days in a month
This example shows how the EDATE function knows the number of days in each month. This takes away the chore of manually adding the different numbers of days.
|=EDATE("5/17/2017",3)||Add 3 months to 5/17/2017||8/17/2017|
|=DATE(2017,5,17)+31+30+31||Add 3 months to 5/17/2017||8/17/2017|
Note how much easier it is to use the EDATE function.
Example 3 - Days in a leap year
The EDATE function knows the number of days in a leap year. Note the two dates highlighted below that are one day different.
|=EDATE("2/17/2015",1)||Add 1 month to 2/17/2015||3/17/2015|
|=EDATE("2/17/2016",1)||Add 1 month to 2/17/2016||3/17/2016|
|=DATE(2015,2,17)+28||Add 28 days to 2/17/2015||3/17/2015|
|=DATE(2016,2,17)+28||Add 28 days to 2/17/2016||3/16/2016|
Live examples in Sheets
Go to this spreadsheet for the examples of the EDATE function shown above that you can study and use anywhere you would like.