You can do this as follows
Copy following code and paste into your macro’s code window

Private Sub addDate()
If TextBox1.Value = "" Then Exit Sub
If TextBox2.Value = "" Then Exit Sub
TextBox3.Value = CDate(TextBox1.Value) + CDbl(TextBox2.Value)
End Sub

Private Sub TextBox1_Change()
Call addDate
End Sub

Private Sub TextBox2_Change()
Call addDate
End Sub

Have a nice time....

Chris
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