Changing Roman Numerals to Arabic

Bradley has a document that has, within text, many Roman numerals. He needs an easy way to change these thousands of Roman numerals to Arabic. These are not fields of any nature; they are simply typed in text as Roman numerals. He wonders if there is a way to easily change them to their Arabic equivalents.

Unfortunately, there is no function in Word that will convert Roman numerals to Arabic. You could, if you want, simply use Find and Replace to search for Roman numerals, but you would have to do an individual search for each one. You could use a wild card search to search for a word that consists entirely of uppercase Roman numerals, which would make searching quite a bit easier. All you need to do is search for "<[CDILMVX]{1,}>" (without the quote marks) and make sure you have the Use Wild Cards check box selected. When you click Find Next, the next Roman numeral is located, and you can then manually change it to its Arabic equivalent.

Another way to try to do the conversion is with a macro. You could create a macro that looks at each word in your document and tries to determine if it is a candidate for consisting of Roman numerals. You may get some false positives, though, particularly if your document contains acronyms that could be confused as Roman numerals. (For example, if you use the acronym CC for credit card, that could be considered the Roman numeral for 200.)

The following set of macros will step through each of the words in a document and if the word contains only Roman numerals (I, V, X, L, C, D, and M) then the user is asked if the macro should convert the numerals.

Sub ConvertRoman()
    Dim wrdX
    Dim wrd As String
    Dim tstSW As Boolean
    Dim J As Long

    For Each wrdX In ActiveDocument.Words
        wrd = UCase(Trim(wrdX))
        If wrd = "" Or wrd = "I" Or wrd = vbCr Then
            tstSW = False
        Else
            tstSW = True
        End If
        For J = 1 To Len(wrd)
            If InStr("MDCLXVI",Mid(wrd, J, 1)) = 0 Then
                tstSW = False
                Exit For
            End If
        Next J

        If tstSW Then
            wrdX.Select
            Selection.MoveLeft unit:=wdCharacter, _
              Count:=Len(wrdX) - Len(wrd), _
              Extend:=wdExtend
            J = MsgBox("Convert " & wrd & " to Arabic", vbYesNoCancel)
            If J = vbCancel Then Exit Sub
            If J = vbYes Then Selection.TypeText Text:=RomanToArabic(wrd)
        End If
    Next wrdX
End Sub

Function RomanToArabic(Rm As String) As String
    Dim J As Long
    Dim ab As Long
    Dim cc As Long
    Dim dd As Long

    ab = 0
    Rm = Trim(Rm)
    J = 1
    Do
        cc = GetValue(Mid(Rm, J, 1))
        dd = GetValue(Mid(Rm, J + 1, 1))
        If cc < dd Then
            ab = ab + dd - cc
            J = J + 1
        Else
            ab = ab + cc
        End If
        J = J + 1
    Loop Until J >= Len(Rm)
    If J = Len(Rm) Then
        ab = ab + GetValue(Mid(Rm, J, 1))
    End If
    RomanToArabic = Trim(Str(ab))
End Function

Function GetValue(ss As String) As Long
    Dim Cde()
    Dim Cvalue()
    Dim J As Long

    Cde = Array("M", "D", "C", "L", "X", "V", "I")
    Cvalue = Array(1000, 500, 100, 50, 10, 5, 1)

    For J = 0 To 6
        If ss = Cde(J) Then
            GetValue = Cvalue(J)
            Exit Function
        End If
    Next J
    GetValue = 999999
End Function

Since an uppercase I is a very common word in text, the macros won't stop on each of them to determine if a conversion should be done. However, if the capital I is part of a longer word that consists of only Roman numerals (such as XLVII), then it is considered a candidate for conversion. The macros also assume that all your Roman numerals are uppercase.

WordTips is your source for cost-effective Microsoft Word training. (Microsoft Word is the most popular word processing software in the world.) This tip (5943) applies to Microsoft Word 2007, 2010, 2013, 2016, 2019, and Word in Microsoft 365. You can find a version of this tip for the older menu interface of Word here: Changing Roman Numerals to Arabic.