Private Sub cmdConvert_Click()
    decimalValue = 0
    base16 = txtNumber.Text    ' base16 is the hexadecimal number
                               ' for example:  FF is base 16 for 255
                               '               10  is 16   100  = 256
                                                 16     10    16     10
                                 A0F would be 10 times 256 = 2560
                                         plus  0 times 16  =    0
                                         plus 15 times 1   =   15
    placeValue = 1                                           -----
                                                             2575
    For i = Len(base16) To 1 Step -1

        c = Mid(base16, i, 1)           ' Using the Mid() string function

        If c >= "0" And c <= "9" Then
            v = Val(c)
        ElseIf c >= "A" And c <= "F" Then    ' A = 10, B = 11, ..., F = 15
            v = Asc(c) - 55 'ascii value
        Else
            Form1.Caption = "base16 Digits Only 0,1,...,E,F"
        End If
            
       decVal = decVal + v * placeValue

       placeValue = placeValue * 16

    Next i
    
    Print "Decimal Value of " & txtNumber & " is " & decVal
    
End Sub