I need to add subtotals to data which varies in both the number of row and
the number of columns.

I can determine the last row and the last column using;
xlApp.Range("A1").Select
z = xlApp.ActiveSheet.UsedRange.Column - 1 +
xlApp.ActiveSheet.UsedRange.Columns.Count
y = xlApp.ActiveSheet.UsedRange.Row - 1 +
xlApp.ActiveSheet.UsedRange.Rows.Count

My question is how do insert into a loop counting the coumn numbers a
calculation that subtotals, the data above it.

I have tried everything I can think of in terms of substituting variables
but no luck

Thanks