Copy and Paste 'X' rows

[Guanjin Peter]

I'm currently using the below code to add the formula in each cell. Depending on the number of rows.
It's very slow (Range("aa2").Value returns 1060) which means 1k rows. I was thinking of doing copy and paste to speed up. But I do not want to fill the whole column U (Column 13) with the formula. Is there anyway to set the max to copy to?
like r2:rX

where X is Range("aa2").Value?

Private Sub CommandButton1_Click()
    Dim nDb As Integer
    intRow = 2
    Range("aa2").Value = "=COUNTA(A:A)-1"
    nDb = Range("aa2").Value
 
       Do While nDb > intRow
                               Var = "=IF(RC2=""Positive Adjmt."",+RC13,IF(RC2=""Negative Adjmt."",-RC13,""Invalid""))"
                ActiveSheet.Range("u" & intRow).End(xlUp).Offset(1, 0).Resize(, 1) = Var
                'Worksheets("nvT").Cells(intRow2, 4).Resize(, cpro).Value = qty
 
        intRow = intRow + 1
        Loop 'end of do-while
End Sub

 

[Guanjin Peter]

ah I see, thank you!