what are you actually summing
these are just the dates
which are correct
ie
=SUMPRODUCT(($G:$G>=DATEVALUE("1/7/2017"))*($G:$G<=DATEVALUE("31/7/2017"))*H:H)
will sum column h for those dates
if counting dates
it works ok for 1st and 31st on my sheet
see attached
these are just the dates
which are correct
ie
=SUMPRODUCT(($G:$G>=DATEVALUE("1/7/2017"))*($G:$G<=DATEVALUE("31/7/2017"))*H:H)
will sum column h for those dates
if counting dates
it works ok for 1st and 31st on my sheet
see attached