Number of repetitions in a collumn and counting those repetitions

Hi,

The best option would be a pivot table. Make sure there's a column label immediately above the first item in column A, click anywhere in column A and choose Insert Pivot Table.
Then drag the column Label into the Row Labels Area and also the Values area
In the values area select the column label drop down and select the COUNT option rather than the default SUM.

Try this...

Data Range

	A	B	C	D
1	ID		ID	Count
2	1		1	2
3	1		3	2
4	2		4	2
5	3		7	2
6	3		8	3
7	4
8	4
9	5
10	6
11	7
12	7
13	8
14	8
15	8
16	------	------	------	------

This array formula** entered in C2:

=IFERROR(INDEX(A:A,SMALL(IF(FREQUENCY(MATCH(A$2:A$15,A$2:A$15,0),ROW(A$2:A$15)-ROW(A$2)+1)>1,ROW(A$2:A$15)),ROWS(C$2:C2))),"")

** array formulas need to be entered using the key
combination of CTRL,SHIFT,ENTER (not just ENTER).
Hold down both the CTRL key and the SHIFT key
then hit ENTER.

This formula entered in D2:

=IF(C2="","",COUNTIF(A:A,C2))

Select C2:D2 and copy down until you get blanks.