H
Herfried K. Wagner [MVP]
First, make sure they are both numeric.
if isnumeric(textbox1.text) and isnumeric(textbox2.text) then
'Then simply add the values
textbox3.text = val(textbox1.text) + val(textbox2.text)
'Val' is not culture-sensitive, which means that it recognizes only the
period (".") as a valid decimal separator. In Germany, for example, "," is
used as decimal separator.