Bob that's perfect when the sheet in question is the activesheet, however this sheet is never available to the user, i adjusted it to this but it fails, could you tell me what i have missed?
eFormula = "IF(OR(AND(MOD('Lookup List'!R1,1)>=--""06:15"",MOD('Lookup List'!R1,1)<=--""07:00""),AND(MOD('Lookup List'!R1,1)>=--""18:15"",MOD('Lookup List'!R1,1)<=--""19:00""))," & _
"INT('Lookup List'!R1)+ROUNDDOWN(MOD('Lookup List'!R1,1)*4,0)/4,'Lookup List'!R1-""00:15"")-" & _
"(NOT(OR(MOD('Lookup List'!R1,1)>=--""17:00"",MOD('Lookup List'!R1,1)<--""07:00"")))"
As i said earlier this has been a development progression that has seen much redundant code...etc, however, i chose to evaluate as that eformula is used and referenced elsewhere in the code for days and nights