What do you have in B3 when it fails? Does B3 always contain an hour
later than B2? Do you enter 00:00 in B3 when you start from 23:00?
This would explain the behavior. If so, try:

=SUMPRODUCT(($A$2:$A$1000=$B2)*($A$2:$1000<$B3+
($B2=TIMEVALUE("23:00")))

Does this help?
Kostis Vezerides

On Jun 7, 6:21 pm, dr350x wrote:
sorry if this is the 2nd post for same question, cant find the 1st post

i have this formula for items per hour.

=SUMPRODUCT(--$A$2:$A$1000=$B2),--($A$2:$1000<$B3))

the data is items per hour, time is military 00:00 to 23:00
formula calculates properly with exception of 23:00 which returns 0.
i have tried different variations of the formular all with the same results
thanks in advance for your help.
--
dr350x