VBA If else statement

Hello peedarp1985,

Your If Then statements are not working because the data being evaluated is a String and not a Number. All data going into and coming out of a TextBox is a String. You will need to convert the text to a number before you test it. It is easier to read using the Select Case statement rather than multiple If Then. Indent your code. It makes it easier to read and to correct.

Private Sub Tolerance_Click()

Dim Msg1 As String
Dim D As Double
Dim L As Double
Dim Ts As Double
Dim S As Double
Dim Ci As Double
Dim Cy As Double

Msg1 = Msg1 & ComboBox1

D = D + Val(TextBox1)
L = L + Val(TextBox2)

Select Case  Msg1
  Case is = "Size"
    Select Case D
      Case Is >= 0.25
        Ts = 0.001 + (0.006 + 0.005 * D)
      Case Is < 0.25
        Ts = 0.001 + (0.003 + 0.016 * D)
    End Select
    MsgBox Ts
  Case Is = "Straightness"
    S = L * 0.0087
    MsgBox S
  Case Is = "Circularity"
    Ci = 0.25 * Size
    MsgBox Ci
  Case Is = "Cylindricity"
    Cy = S + Ci
    MsgBox Cy
End Select

End Sub