Lots of ways on the Web and here's one:-

http://www.meadinkent.co.uk/xlnumberstext.htm

Mike

Here is the response I posted to this very same question yesterday
afternoon....

Go into the VB Editor (Alt+F11) and add a Module to the Workbook
(Insert/Module from the VBA menu) and then paste in all of the code
appearing after my signature. You can call the function from your work sheet
like this =NumberAsText(A1) where A1 is assume to hold the number you want
to convert. There is an Optional argument you can use to format the results
to your liking. Here are some examples to show the options available...

A1:  123.45
In B1:
=NumberAsText(A1)  ==>  One Hundred Twenty Three Point Four Five
=NumberAsText(A1"And")  ==>  One Hundred and Twenty Three Point Four Five
=NumberAsText(A1,"Check")  ==>  One Hundred Twenty Three and 45/100
=NumberAsText(A1,"Dollar")  ==>  One Hundred Twenty Three Dollars and Forty
Five Cents

To summarize, using "And" adds the word "and" in front of the tens/units
text; using "Check" formats any decimal values as would be written on a
check; and using "Dollar" adds the words "Dollars" and "Cents" in their
appropriate positions. The code is laid out in a reasonably straight forward
manner, so if Dollars/Cents is not you native currency designation, you
should be able to modify the program accordingly. In addition to the above,
for all modes, the Plus and Minus sign can be used and will be reported back
as a word; commas may be used to separate the numbers to the left of the
decimal point but they will not be reported back by the routine and are
permitted for the users convenience (however, if commas are used, they must
be placed in their correct positions). And, finally,if I remember correctly,
this function will work with a whole number part up to one less than a
quintillion (you can have as many decimal points as desired), but remember
to format large numbers as Text values... VB will convert large non-Text
values to Doubles (which will destroy the conversion).

Rick

Private sNumberText() As String

Public Function NumberAsText(NumberIn As Variant, _
               Optional AND_or_CHECK_or_DOLLAR As String) As String
  Dim cnt As Long
  Dim DecimalPoint As Long
  Dim CardinalNumber As Long
  Dim CommaAdjuster As Long
  Dim TestValue As Long
  Dim CurrValue As Currency
  Dim CentsString As String
  Dim NumberSign As String
  Dim WholePart As String
  Dim BigWholePart As String
  Dim DecimalPart As String
  Dim tmp As String
  Dim sStyle As String
  Dim bUseAnd As Boolean
  Dim bUseCheck As Boolean
  Dim bUseDollars As Boolean
 '----------------------------------------
 '  Begin setting conditions for formatting
 '----------------------------------------
 '  Determine whether to apply special formatting.
 '  If nothing passed, return routine result
 '  converted only into its numeric equivalents,
 '  with no additional format text.
  sStyle = LCase(AND_or_CHECK_or_DOLLAR)
 '  User passed "AND": "and" will be added
 '  between hundredths and tens of dollars,
 '  ie "Three Hundred and Forty Two"
  bUseAnd = sStyle = "and"
 '  User passed "DOLLAR": "dollar(s)" and "cents"
 '  appended to string,
 '  ie "Three Hundred and Forty Two Dollars"
  bUseDollars = sStyle = "dollar"
 '  User passed "CHECK" *or* "DOLLAR"
 '  If "check", cent amount returned as a fraction /100
 '  i.e. "Three Hundred Forty Two and 00/100"
 '  If "dollar" was passed, "dollar(s)" and "cents"
 '  Appended instead.
  bUseCheck = (sStyle = "check") Or (sStyle = "dollar")
 '----------------------------------------
 '  Check/create array. If this is the first
 '  time using this routine, create the text
 '  strings that will be used.
 '----------------------------------------
  If Not IsBounded(sNumberText) Then
     Call BuildArray(sNumberText)
  End If
 '----------------------------------------
 '  Begin validating the number, and breaking
 '  into constituent parts
 '----------------------------------------
 '  Prepare to check for valid value in
  NumberIn = Trim$(NumberIn)
  If Not IsNumeric(NumberIn) Then
    '  Invalid entry - abort
     NumberAsText = "Error - Number improperly formed"
     Exit Function
  Else
    '  Decimal check
     DecimalPoint = InStr(NumberIn, ".")
     If DecimalPoint > 0 Then
       '  Split the fractional and primary numbers
        DecimalPart = Mid$(NumberIn, DecimalPoint + 1)
        WholePart = Left$(NumberIn, DecimalPoint - 1)
     Else
       '  Assume the decimal is the last char
        DecimalPoint = Len(NumberIn) + 1
        WholePart = NumberIn
     End If
     If InStr(NumberIn, ",,") Or _
        InStr(NumberIn, ",.") Or _
        InStr(NumberIn, ".,") Or _
        InStr(DecimalPart, ",") Then
        NumberAsText = "Error - Improper use of commas"
        Exit Function
     ElseIf InStr(NumberIn, ",") Then
        CommaAdjuster = 0
        WholePart = ""
        For cnt = DecimalPoint - 1 To 1 Step -1
           If Not Mid$(NumberIn, cnt, 1) Like "[,]" Then
              WholePart = Mid$(NumberIn, cnt, 1) & WholePart
           Else
              CommaAdjuster = CommaAdjuster + 1
              If (DecimalPoint - cnt - CommaAdjuster) Mod 3 Then
                 NumberAsText = "Error - Improper use of commas"
                 Exit Function
              End If
           End If
        Next
     End If
  End If
  If Left$(WholePart, 1) Like "[+-]" Then
     NumberSign = IIf(Left$(WholePart, 1) = "-", "Minus ", "Plus ")
     WholePart = Mid$(WholePart, 2)
  End If
 '----------------------------------------
 '  Begin code to assure decimal portion of
 '  check value is not inadvertently rounded
 '----------------------------------------
  If bUseCheck = True Then
     CurrValue = CCur(Val("." & DecimalPart))
     DecimalPart = Mid$(Format$(CurrValue, "0.00"), 3, 2)
     If CurrValue >= 0.995 Then
        If WholePart = String$(Len(WholePart), "9") Then
           WholePart = "1" & String$(Len(WholePart), "0")
        Else
           For cnt = Len(WholePart) To 1 Step -1
             If Mid$(WholePart, cnt, 1) = "9" Then
                Mid$(WholePart, cnt, 1) = "0"
             Else
                Mid$(WholePart, cnt, 1) = _
                           CStr(Val(Mid$(WholePart, cnt, 1)) + 1)
                Exit For
             End If
           Next
        End If
     End If
  End If
 '----------------------------------------
 '  Final prep step - this assures number
 '  within range of formatting code below
 '----------------------------------------
  If Len(WholePart) > 9 Then
     BigWholePart = Left$(WholePart, Len(WholePart) - 9)
     WholePart = Right$(WholePart, 9)
  End If
  If Len(BigWholePart) > 9 Then
     NumberAsText = "Error - Number too large"
     Exit Function
  ElseIf Not WholePart Like String$(Len(WholePart), "#") Or _
        (Not BigWholePart Like String$(Len(BigWholePart), "#") _
         And Len(BigWholePart) > 0) Then
     NumberAsText = "Error - Number improperly formed"
     Exit Function
  End If
 '----------------------------------------
 '  Begin creating the output string
 '----------------------------------------
 '  Very Large values
  TestValue = Val(BigWholePart)
  If TestValue > 999999 Then
     CardinalNumber = TestValue \ 1000000
     tmp = HundredsTensUnits(CardinalNumber) & "Quadrillion "
     TestValue = TestValue - (CardinalNumber * 1000000)
  End If
  If TestValue > 999 Then
    CardinalNumber = TestValue \ 1000
    tmp = tmp & HundredsTensUnits(CardinalNumber) & "Trillion "
    TestValue = TestValue - (CardinalNumber * 1000)
  End If
  If TestValue > 0 Then
     tmp = tmp & HundredsTensUnits(TestValue) & "Billion "
  End If
 '  Lesser values
  TestValue = Val(WholePart)
  If TestValue = 0 And BigWholePart = "" Then tmp = "Zero "
  If TestValue > 999999 Then
     CardinalNumber = TestValue \ 1000000
     tmp = tmp & HundredsTensUnits(CardinalNumber) & "Million "
     TestValue = TestValue - (CardinalNumber * 1000000)
  End If
  If TestValue > 999 Then
     CardinalNumber = TestValue \ 1000
     tmp = tmp & HundredsTensUnits(CardinalNumber) & "Thousand "
     TestValue = TestValue - (CardinalNumber * 1000)
  End If
  If TestValue > 0 Then
     If Val(WholePart) < 99 And BigWholePart = "" Then bUseAnd = False
     tmp = tmp & HundredsTensUnits(TestValue, bUseAnd)
  End If
 '  If in dollar mode, assure the text is the correct plurality
  If bUseDollars = True Then
     CentsString = HundredsTensUnits(DecimalPart)
     If tmp = "One " Then
        tmp = tmp & "Dollar"
     Else
        tmp = tmp & "Dollars"
     End If
     If Len(CentsString) > 0 Then
        tmp = tmp & " and " & CentsString
        If CentsString = "One " Then
           tmp = tmp & "Cent"
        Else
           tmp = tmp & "Cents"
        End If
     End If
  ElseIf bUseCheck = True Then
     tmp = tmp & "and " & Left$(DecimalPart & "00", 2)
     tmp = tmp & "/100"
  Else
     If Len(DecimalPart) > 0 Then
       tmp = tmp & "Point"
       For cnt = 1 To Len(DecimalPart)
         tmp = tmp & " " & sNumberText(Mid$(DecimalPart, cnt, 1))
       Next
     End If
  End If
 '  Done!
  NumberAsText = NumberSign & tmp
End Function

Private Sub BuildArray(sNumberText() As String)
  ReDim sNumberText(0 To 27) As String
  sNumberText(0) = "Zero"
  sNumberText(1) = "One"
  sNumberText(2) = "Two"
  sNumberText(3) = "Three"
  sNumberText(4) = "Four"
  sNumberText(5) = "Five"
  sNumberText(6) = "Six"
  sNumberText(7) = "Seven"
  sNumberText(8) = "Eight"
  sNumberText(9) = "Nine"
  sNumberText(10) = "Ten"
  sNumberText(11) = "Eleven"
  sNumberText(12) = "Twelve"
  sNumberText(13) = "Thirteen"
  sNumberText(14) = "Fourteen"
  sNumberText(15) = "Fifteen"
  sNumberText(16) = "Sixteen"
  sNumberText(17) = "Seventeen"
  sNumberText(18) = "Eighteen"
  sNumberText(19) = "Nineteen"
  sNumberText(20) = "Twenty"
  sNumberText(21) = "Thirty"
  sNumberText(22) = "Forty"
  sNumberText(23) = "Fifty"
  sNumberText(24) = "Sixty"
  sNumberText(25) = "Seventy"
  sNumberText(26) = "Eighty"
  sNumberText(27) = "Ninety"
End Sub

Private Function IsBounded(vntArray As Variant) As Boolean
 '  Note: the application in the IDE will stop
 '  at this line when first run if the IDE error
 '  mode is not set to "Break on Unhandled Errors"
 '  (Tools/Options/General/Error Trapping)
  On Error Resume Next
  IsBounded = IsNumeric(UBound(vntArray))
End Function

Private Function HundredsTensUnits(ByVal TestValue As Integer, _
                             Optional bUseAnd As Boolean) As String
  Dim CardinalNumber As Integer
  If TestValue > 99 Then
     CardinalNumber = TestValue \ 100
     HundredsTensUnits = sNumberText(CardinalNumber) & " Hundred "
     TestValue = TestValue - (CardinalNumber * 100)
  End If
  If bUseAnd = True Then
     HundredsTensUnits = HundredsTensUnits & "and "
  End If
  If TestValue > 20 Then
     CardinalNumber = TestValue \ 10
     HundredsTensUnits = HundredsTensUnits & _
                         sNumberText(CardinalNumber + 18) & " "
     TestValue = TestValue - (CardinalNumber * 10)
  End If
  If TestValue > 0 Then
     HundredsTensUnits = HundredsTensUnits & _
                         sNumberText(TestValue) & " "
  End If
End Function

See http://www.xldynamic.com/source/xld.xlFAQ0004.html