Summary
To get the same date next month from a given date, you can use the EDATE function. In the worksheet shown, the formula in cell C5 is:
=EDATE(B5,1)
As the formula is copied down, it returns the same date in the next month after the date in column B.
Generic formula
=EDATE(date,1)
Explanation
The EDATE function returns a date on the same day of the month, n months in the past or future. You can use EDATE to calculate expiration dates, maturity dates, and other due dates. When 1 is given for months, EDATE returns the same date in the next month. Notice that EDATE automatically handles end-of-month dates properly, adjusting the day when needed to return a valid date.
Same date in the previous month
To get the same date in the previous month, use -1 for months:
=EDATE(date,-1) // prior month
