Not sure what you mean by a "a Modulo 43 spreadsheet", but this function
calculates the check digit according to the Modulo 43 applied to the CODE 39
encoding logic.
You should add checks for valid input.
Public Function GetModulo43(CodeText As String) As String
Dim CharValues() As String
Dim i As Long
Dim RunSum As Long
Const Chars As String =
"0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,-,.
, ,$,/,+,%"
CharValues = Split(Chars, ",")
For i = 1 To Len(CodeText)
RunSum = RunSum + Application.WorksheetFunction.Match(Mid(CodeText, i,
1), CharValues, 0) - 1
Next
GetModulo43 = CharValues(RunSum Mod 43)
End Function
NickHK