Textbox Change Event Error on Backspace --VBA Userform

Question

I have 2 Text boxes on a user form: tbQty1, tbQty2. I want tbQty2 value to equal tbQty1.value * 2. The following simple code [_Change()] works unless I delete or backspace out the value of tbQty1. I get an run time error 13 type mismatch

Private Sub tbQty1_Change()

tbQty2.Value = tbDoorQty.Value * 2

End Sub

I have tried IF statements with tbQty1.value = "" etc. and Keypress ( IF KeyAscii = 8 Then tbQty1 = "" ). All blew up the same way I'm just missing something. Thanks for the help

Answer 1

If isnumeric(tbQty1.value) then
 'statements
end if