I'm trying to sum using vb from cell e3 to the bottom of the row which
will be a variable number of rows. For some reason, it doesn't like
the last line in my code. I think I may have done something wrong at
the end of the last line.

Dim Rng As Range
Set Rng = Range ("e3").End(xlDown)
rng.Offset (1,0).Formula="=SUM(E"&rng.row&")"