A B C D E
Time Count
0:16:24 1 =A2 =C2+10/(24*60*60) formula below
0:16:40 1 =D2 =C3+10/(24*60*60) drag down
0:16:49 1 =D3 drag down
0:16:51 2
0:17:02 1
0:17:11 1

Formula:
=SUMPRODUCT(--($A$2:$A$7=C2),--($A$2:$A$7<D2),$B$2:$B$7)

Adjust ranges!

Regards,
Stefi

I want to say, group and auto-sum the data for intervals of every 10 seconds
starting with the first time value. So I'd expect something like:
0:16:24 - 0:16:34 1
0:16:34 - 0:16:44 1
0:16:44 - 0:16:54 3
0:16:54 - 0:17:04 1
0:17:04 - 0:17:14 1

or I'll even take within a window of 10 seconds starting from each
successive value like:
0:16:24-0:16:34 1
0:16:40-0:16:49 2
0:16:51-0:17:01 2
0:17:02-0:17:12 2

Thanks for any help you can provide.

Jon