Formula to add incremental values

[SONART]

Hi All!

Hope everyone had a great festive season and a Happy New Year!

I'm having trouble putting together a formula to perform the following below:

1. I had to calculate the number of months between the dates in cell A1 which is the latest actual data (01/12/13) and cell A2 which is the projected date (01/12/14). In this example A2 - A1 = 12 months. This will change based on the current or latest data I receive on a monthly basis.

2. I then created a drop down list with the following values: 6, 12 and 18. If I select 6 as an example it will list the values 1 - 6 (see below).

List of values within each cell
A4 1
A5 2
A6 3
A7 4
A8 5
A9 6

If I select 12, it will list down the values from 1 to 12.
If I select 18, it will list down the values from 1 to 18.

Problem: I would like to add 12 (derived from point 1) on the list of values (derived from point 2). Therefore as shown below, if I select 6 it will list values 1 to 6 and then add from the list 12, resulting into 1 - 18 (see below).

List of values within the cells
A4 1
A5 2
A6 3
A7 4
A8 5
A9 6
A10 7
A11 8
A12 9
A13 10
A14 11
A15 12
A16 13
A17 14
A18 15
A19 16
A20 17
A21 18

If I select 12, it will list down values 1 to 24 (12 + 12).
If I select 18, it will list down values 1 to 30 (18 + 12).

I hope this makes sense and any assistance would be much appreciated.

SONART

 

[Snakehips]

SONART,

Try....

Excel 2007
	A
1	01/12/2013
2	01/12/2014
3	6
4	1
5	2
6	3
7	4
8	5
9	6
10	7
11	8
12	9
13	10
14	11
15	12
16	13
17	14
18	15
19	16
20	17
21	18
Sheet1

Cell Formulas
Range	Formula
A4	=IF(ROWS(A$4:A4)<=$A$3+DATEDIF($A$1,$A$2,"m"),ROWS(A$4:A4),"")

Hope that helps.

 

[SONART]

Many thanks SNAKEHIPS, much appreciated! It appears to be working perfectly!