Count Time Entries VBA

[healey21]

I have been asked if this is possible, A column holds date and time entries and we have been asked to count entries for every 15 minutes from the first entry and then show the count in the column to the right, I suspect that this can only be done via VBA but not sure of the approach. A sample is shown below:

Excel Workbook
	B	C	D
1	Time Completed	Total Count Every 15 Mins	Comment
2	19/08/2011 15:30
3	19/08/2011 15:31
4	19/08/2011 15:32
5	19/08/2011 15:33
6	19/08/2011 15:35
7	19/08/2011 15:37
8	19/08/2011 15:40
9	19/08/2011 15:42
10	19/08/2011 15:43
11	19/08/2011 15:44	10	Because start time is 15:30
12	19/08/2011 15:48
13	19/08/2011 15:50
14	19/08/2011 15:52
15	19/08/2011 15:53
16	19/08/2011 15:55
17	19/08/2011 15:56	6	Because start time is 15:48
18	19/08/2011 16:03
19	19/08/2011 16:04
20	19/08/2011 16:08
21	19/08/2011 16:11
22	19/08/2011 16:16
23	19/08/2011 16:17	6	Because start time is 16:04
24	19/08/2011 16:19
25	19/08/2011 16:20
26	19/08/2011 16:22
27	19/08/2011 16:23
Time Count

 

[healey21]

Bump

 

[AlphaFrog]

Put this in C2 and drag down.

=IF(B3="","",IF(MINUTE(B3-IF(COUNT($C$1:C1),INDEX(B:B,MATCH(999,$C$1:C1,1)+1),$B$2))>=15,
                   ROW()-IF(COUNT($C$1:C1),MATCH(999,$C$1:C1,1),1),""))

 

[healey21]

Thank you AlphaFrog this works a treat. I have extended this through the thousands of rows.