processing a string by Excel

I think this will do what you want - It can only cope with one lot of multiple (( & )) brackets

It only looks at cell A1 & displays the result in a message box

Code can be modified to run down a column & place the result into another column

Sub ConvertTxtToFormula()
   Dim i4Cnt As Integer
   Dim sCellTxt As String
   Dim sParam As String
   Dim sChar As String
   Dim sFormula As String
   
   Dim iPos(4) As Integer
   
   sCellTxt = Range("a1").Value
   
   For i4Cnt = 1 To Len(sCellTxt) Step 1
      sChar = Mid(sCellTxt, i4Cnt, 1)
      Select Case sChar
      Case "("
         If i4Cnt = 1 Then
            iPos(0) = 1
            iPos(1) = i4Cnt
         Else
            iPos(1) = i4Cnt + 1
         End If
      Case ")"
         If Mid(sCellTxt, i4Cnt - 1, 2) = "))" Then
            iPos(1) = i4Cnt - 1
         End If
         iPos(0) = (i4Cnt) - iPos(1)
      Case "-", "+,", "/", "*", "^"
         iPos(1) = i4Cnt
         iPos(0) = 1
      End Select
      If iPos(0) > 0 Then
         sParam = Mid(sCellTxt, iPos(1), iPos(0))
         iPos(0) = 0
         Select Case Right(sFormula, 1)
         Case "-", "+,", "/", "*", "^", ""
            sFormula = sFormula & sParam
         Case Else
            Select Case sParam
            Case "-", "+,", "/", "*", "^"
               sFormula = sFormula & sParam
            Case Else
               sFormula = sFormula & "*" & sParam
            End Select
            If sParam = ")" Then
               sParam = Trim(Mid(sCellTxt, i4Cnt + 1))
               Select Case sParam
               Case "-", "+,", "/", "*", "^"
                  sFormula = sFormula & sParam
               Case Else
                  sFormula = sFormula & "*" & sParam
               End Select
               Exit For
            End If
         End Select
      End If
   Next i4Cnt
   MsgBox sFormula
End Sub

Mark

It's taken a while to get all the bugs out.

The answers you supplied for the last 2 equations, to me appears to be incorrect - You left a ] in both of them & the last one is missing the 1st )

The extra examples helped me to code the macro to deliver the results you are after

This macro loops through column A starting at row 1 to the last used row in column A, Places the result in column B of the same row

Please test as fully as possible.

Sub ExtractFormula()
   Dim bAdd As Boolean
   
   Dim iTxtLen As Integer
   Dim i4Len As Integer
   
   Dim l4Row As Long
   
   Dim sCval As String
   Dim sFormula As String
   Dim sParam As String
   Dim sOp As String
   
   For l4Row = 1 To Cells(Rows.Count, "a").End(xlUp).Row Step 1
      sCval = Cells(l4Row, "a")
      iTxtLen = Len(sCval)
      
      bAdd = True
      For i4Len = 1 To iTxtLen Step 1
         Select Case Mid(sCval, i4Len, 1)
         Case "(", ")"
            If Len(sOp) = 1 Then
               sFormula = sFormula & sOp & sParam
               sOp = vbNullString
            Else
               If Len(sParam) > 0 Then
                  Select Case sParam
                  Case "-", "+", "/", "*", "^"
                     sFormula = sFormula & sParam
                  Case Else
                     sFormula = sFormula & "*" & sParam
                  End Select
               End If
            End If
            sParam = vbNullString
            sFormula = sFormula & Mid(sCval, i4Len, 1)
            bAdd = True
         Case " "
            bAdd = True
            If Len(sParam) > 0 Then
               Select Case sParam
               Case "-", "+", "/", "*", "^"
                  sOp = sParam
               Case Else
                  If Len(sOp) = 1 Then
                     sFormula = sFormula & sOp & sParam
                     sOp = vbNullString
                  Else
                     If Right(sFormula, 1) = "(" Then
                        sFormula = sFormula & sParam
                     Else
                        Select Case Left(sParam, 1)
                        Case "-", "+", "/", "*", "^"
                           sFormula = sFormula & sParam
                        Case Else
                           sFormula = sFormula & "*" & sParam
                        End Select
                     End If
                  End If
               End Select
            End If
            sParam = vbNullString
         Case Else
            Select Case Mid(sCval, i4Len, 1)
            Case "["
               sParam = vbNullString
            Case "]"
               bAdd = False
            Case Else
               If bAdd = True Then
                  sParam = sParam & Mid(sCval, i4Len, 1)
               End If
            End Select
         End Select
      Next i4Len
      If Len(sParam) > 0 Then
         If Len(sOp) = 1 Then
            sFormula = sFormula & sOp & sParam
         Else
            sFormula = sFormula & "*" & sParam
         End If
      End If
      Cells(l4Row, "b").Value = sFormula
      sFormula = vbNullString
      sOp = vbNullString
      sParam = vbNullString
   Next l4Row
End Sub