Re: How to sum every 12th cell in my data

Images are a bit difficult for us to work with....sample files are better.

Just looking at your formula, I think you'd need a way to increment the MOD value.
Try something like this, copied down:

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Is that something you can work with?

No...
ROWS($2:2) initially resolves to 1...then, when copied down,
ROWS($2:3) returns 2
ROWS($2:4) returns 3
...etc

Those values are compared to what the MOD function calculates, thereby matching on every 12 row...but, matching different sets each time.

The formula is summing U14 and U26 etc. The first cell is U14 because your data starts in U3. With U3 being the first value, the 12th value is U14. (Count them if you like) The next values are in U26, U36, U48 etc.

I prefer to use this form of the formula because I just find it easier. (entered in T3)

Formula:

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If Ron Coderre's formula was written like this and entered in W3 the Rows($2:3) would be equivalent to the 2 that I used. As you can see the results are identical. It is just a matter of choice.

Formula:

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Column V has the result of the formula

Formula:

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	T	U	V	W
3	120	1	3	120
4		2	4
5		3	5
6		4	6
7		5	7
8		6	8
9		7	9
10		8	10
11		9	11
12		10	0
13		11	1
14		12	2
15		13	3
16		14	4
17		15	5
18		16	6
19		17	7
20		18	8
21		19	9
22		20	10
23		21	11
24		22	0
25		23	1
26		24	2
27		25	3
28		26	4
29		27	5
30		28	6
31		29	7
32		30	8
33		31	9
34		32	10
35		33	11
36		34	0
37		35	1
38		36	2
39		37	3
40		38	4
41		39	5
42		40	6
43		41	7
44		42	8
45		43	9
46		44	10
47		45	11
48		46	0
49		47	1
50		48	2
51		49	3

Here is a modification of the formula that I gave you which relies upon the values produced by this formula that gives a value for each month:
Enter this in column Z3 (January) and copy down for 12 rows in total:

Formula:

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This gives January 3, February 4, March 5, April 6 etc. until October is 0 then November is 1 and December is 2.

Enter this in W3 and fill down 12 rows:

Formula:

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This formula will give you the same results. Enter in W3 and fill down for a total of 12 rows. This SUMIF just sums the values for each month.

Formula:

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Easiest of all is a Pivot table.

I have shown in column Q the repetition of values produced by the MOD formula.