Countifs between dates and also blank cell

[Yelruh]

So I have the formula figured out for between dates to calculate what I have on hand C11 being the date, however whats stumping me is to count if no date is in the BK column???

=COUNTIFS('10-16'!$BK:$BK,">="&C11,'10-16'!$S:$S,"<="&C11,'10-16'!$D:$D,"Cat")

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[Tetra201]

Maybe

=COUNTIFS('10-16'!$BK:$BK,">="&C11,'10-16'!$S:$S,"<="&C11,'10-16'!$D:$D,"Cat")+COUNTIFS('10-16'!$BK:$BK,"",'10-16'!$S:$S,"<="&C11,'10-16'!$D:$D,"Cat")

 

[Yelruh]

Eureka!!!!!! Thank you!!!! it worked

 

[Tetra201]

Glad to have been of help.