Try to extend your formula this way:

{=IF(AND(MAX(COUNTIF('Daniel S'!A4:A1000,A4:A1000))1,MAX(COUNTIF('Next
sheet'!A4:A1000,A4:A1000))1, ... ),"Duplicate","No
Duplicates")}

Regards,
Stefi

€žRAYCV€� ezt Ã*rta:

Hi, I am using the following array formula to check for duplicates within a
worksheet.

{=IF(MAX(COUNTIF('Daniel S'!A4:A1000,A4:A1000))1,"Duplicate","No
Duplicates")}

Is there a way that I can extend this so that it checks the same range
across 10 worksheets within a workbook.

Thanks