"SuperJas" wrote...
The easiest method is to use the Find and Replace.

Except that finding 2003 and replacing it with 2004 will change numbers like
120034 into 120044 and 1.2003 into 1.2004, as well as changing cell
references like AB2003 into AB2004, which are unlikely to be what the OP
wants to do. There are times when easiest isn't correct.

The following is possibly overkill, but it changes only instances of 2003
that appear as distinct, full tokens. One flaw: it changes tokens inside
string constants. No way to prevent that without writing most of a formula
parser.


Function Subst(orig_text As String, _
match_pat As String, _
replace_pat As String, _
Optional instance As Variant _
) As Variant
'------------------------------------------------------
Dim regex As Object, matches As Object, m As Object

Set regex = CreateObject("vbscript.regexp")
regex.Pattern = match_pat
regex.Global = True

If (IsMissing(instance)) Then
Subst = regex.Replace(orig_text, replace_pat)
ElseIf instance 0 Then
Set matches = regex.Execute(orig_text)
If instance matches.Count Then
Subst = orig_text 'matchnum out of bounds - do nothing
Else
Set m = matches.Item(instance - 1)
Subst = Left(orig_text, m.FirstIndex) & _
regex.Replace(m.Value, replace_pat) & _
Right(orig_text, Len(orig_text) - m.FirstIndex - m.Length)
End If
Else
Subst = CVErr(xlErrValue) 'invalid: instance <= 0
End If
End Function


Sub foo()
Dim ws As Worksheet, c As Range, cf As String, nf As Variant

Application.Calculation = xlCalculationManual

For Each ws In ActiveWorkbook.Worksheets
For Each c In ws.UsedRange
If c.HasFormula Then
cf = c.Formula
nf = Subst(cf, "(^|[^.])\b2003\b(?!\.)", "$12004")
If Not IsError(nf) And CStr(nf) < cf Then
If c.HasArray Then
c.FormulaArray = nf
Else
c.Formula = nf
End If
End If
End If
Next c
Next ws

Application.Calculation = xlCalculationAutomatic
Application.Calculate

End Sub