Hi
I am trying to reduce the processing time of a spreadsheet that contains the following formula. The constants need to remain constant but the rest will need to reflect the position in the worksheet e.g. as it would if it the formula were copied across columns.

=IF(AND($K10>=X$4,$K10<Y$4),$K$6,IF(X$3="XSD","Xmas",IF(AND($L10>=X$4,$L10< Y$4),$L$6,IF(AND($M10>=X$4,$M10<Y$4),$M$6,IF(AND($N10>=X$4,$N10<Y$4),$N$6,I F(AND($O10>=X$4,$O10<Y$4),$O$6,IF(AND($P10>=X$4,$P10<Y$4),$P$6,IF(AND($S10> =X$4,$S10<Y$4),$S$6,IF(AND($R10>=X$4,$R10<Y$4),$R$6,IF(AND($Q10>=X$4,$Q10<Y $4),$Q$6,IF(OR(Y10=$K$6,Y10=$L$6,Y10=$M$6,Y10=$N$6,Y10=$O$6,Y10=$P$6),SUM(M AX(Y10:AE10)+1),IF(AND(Y10>0,Y10<10),SUM(MAX(Y10:AE10)+1),IF(Y10="Aircon"," ",IF(Y10="","",IF(AND(Y10="Xmas",Z10="Xmas",OR(AA10="",AA10="Aircon")),"",S UM(MAX(Y10:AE10)+1))))))))))))))))

Any assistance converting this into a VBA function would be much appreciated.