If you are up for a macro solution, then you might want to consider this...

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Not Intersect(Target, Range("D:D")) Is Nothing Then
Target.NumberFormat = "@"
End If
End Sub

Private Sub Worksheet_Change(ByVal Target As Range)
Dim Entry As String
On Error GoTo Whoops
Entry = Replace(Target.Text, " ", "")
Application.EnableEvents = False
If Not Entry Like "*[!0-9]*" And Len(Entry) = 16 Then
Target.Value = Format$(Entry, "@@@@ @@@@ @@@@ @@@@")
ElseIf Not Entry Like "*[!0-9]*" Then
Target.NumberFormat = "General"
Target.Value = CDbl(Target.Value)
End If
Whoops:
Application.EnableEvents = True
End Sub

It lets you type in your number with or without the separating spaces. If
your number is not 16 digits long or if a non-number is entered, then the
entry is left as is; however, if your entry has 16 digits (with or without
spaces), then it will be formatted in groups of 4. As written for this
example, only values in Column D will be processed... change the Range shown
in the Intersect method to those columns or cells you want your spreadsheet
to process.

Rick



"littlesword" wrote in message
...
I want to format a cell wherein spaces will be automatically added to the
numbers that I will type. The format should be like this 1111 2222 3333
4444.
I was able to make this format but the problem is, it always replace my
last
number to 0. For example, if I type 5462 5700 0123 4568 it would be
displayed
as 5462 5700 0123 4568. The custom format I used was #### #### #### ####.
What should I change with this format?