Any date field can be used in a calculated field to add x number of days from the date field.
quote The number of payments can change. quote
When asking for advice or a solution, the best most in depth description is helpful.
If I add 15 to the date of the first payment (15/10/09) I get 30/10/09 that it´s ok, but if I add 15 to the date (30/10/09) of the second payment I get 14/11/09 because October has 31 days. How Can I take into consideration that a month can have 28, 29 30 and 31 days.
Regarding the number of payments can change, I can schedule X number of payments, is not a fixed number.
With 2 payments: 1st = 15/10/09 ; 2nd = 15/10/09 + 15 = 30/10/09. ok
With 3 payments: 1st = 15/10/09 ; 2nd = 15/10/09 + 15 = 30/10/09 ; 3rd = 30/10/09 + 15 = 14/11/09. not ok.
With 4 payments: 1st = 30/10/09 ; 2nd = 30/10/09 + 15 = 14/11/09 ; 3rd = 14/11/09 + 15 = 29/11/09 ; 4th = 29/11/09 + 15 = 14/12/09
There's a Date function you can use for this purpose:
Date (Month(YourDateField, 15, Year(YourDateField))
will take a date entered in YourDateField and return a date for the 15th of the same month and year. Many more sophisticated versions can be built from this function if you need them.
Many thanks all