Good morning,

I am looking for assistance to see if there is a way to improve a SUMPRODUCT formula I have. The formula works as it should, but will lock my computer up when filling the formula down to all rows. My spreadsheet this is running on usually has anywhere from 35,000 to 40,000 rows. Please let me know if there are any changes that can be made to help this formula run more efficiently.

=IF(SUMPRODUCT(($BM$3:$BM3=BM3)*($CU$3:$CU3=CU3))>1,0,1)

I am trying to enter a 1 when values in columns BM and CU for a specific row are the first occurrence of each combination.

Thanks.