I have contiguous data starting in c5. The last row and
the number of columns is not known.

I can select the data cells with the following code:
Range(Selection, Selection.End(xlDown)).Select
Range(Selection, Selection.End(xlToRight)).Select

However, how do I extend this selection by one row.

Say that I have selected range C5:J14. How would I be able
to select C5:J15? I would like to extend the selection
without hardcoding it by one row so that I can get the row
totals.

Thanks for your help.