Calculating # of monthly periods between two dates...

I want to calculate the number of payments that have been made on a mortgage between two dates (the first date being the first payment date and the other date being some random date in the future).

Payments are made monthly on the same day of the month. So, if the first payment date is 2/15/1999 then the next payment will be made on 3/15/1999, and the third payment on 4/15/1999, etc.

So basically I need a formula that counts how many times a particular day (determined by the day of first payment) occurs each month between two dates, e.g. between 5/15/2005 and 7/14//2006 the 15th day of the month occurs 14 times (including the first payment date).

Let's say I want to know how many payments were made between 2/1/1999 and 3/25/2011 (REMEMBER: payments are made on the 1st of the month in this case), what would the formula be for figuring that out???

NOTE:
A1: First Payment Date
A2: Second Date (any future date, not necessarily a payment date)

I've used, to no avail, =DATEIF(A1,A2,"m"). This function doesn't account for the fact that payments are made on the same day of each month. For example, with A1:1/1/2011 and A2: 3/31/2011 the formula returns 2 months even though 3 months of payments would have been made.

Can you produce a formula that counts the number of payments between two dates, recognizing that the day of first payment will be the day on which each following monthly payment is made???

THanks in advance.

Originally Posted by shg

Welcome to the forum.

How about =DATEDIF(A1, A2, "m")+1

HAHA I think that might just be it! I'll try some different dates to test it out though.

Thanks