Setting a Length Limit on Cells

Craig is developing a worksheet and wants to know if there is a way to specify the maximum number of characters that can be entered in any given cell. He doesn't want to use Data Validation to impose the limitation.

There is no way to do this directly in Excel without (as Craig mentions) using Data Validation. There are a few things you can try to achieve the desired effect, however. First, you can using a formula to check the length of any cell, and then display an error message, if desired. For instance, if the cells you want to check are in column C, you could use a formula such as the following:

=IF((LEN(C1)>15),"Cell is Too Long","")

Place the formula in the cell to the right of the cell being checked (such as in cell D1), and then copy it down as many cells as necessary. When an entry is made in C1, and if it is more than 15 characters, then the message is displayed.

If such a direct approach is undesirable, then you'll need to use macros to do the checking. The following is a simple example that is triggered whenever something is changed in the worksheet. Each cell in the worksheet is then checked to make sure it is not longer than 15 characters. If such a cell is discovered, then a message box is displayed and the cell is cleared.

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    For Each cell In UsedRange
        If Len(cell.Value) > 15 Then
            MsgBox " Can't enter more than 15 characters"
            cell.Value = ""
        End If
    Next
End Sub

A more robust approach is to check in the event handler to see if the change was made somewhere within a range of cells that need to be length-limited.

Private Sub Worksheet_Change(ByVal Target As Excel.Range)
    Dim rng As Range
    Dim rCell As Range
    Dim iChars As Integer
    On Error GoTo ErrHandler

    'Change these as desired
    iChars = 15
    Set rng = Me.Range("A1:A10")

    If Not Intersect(Target, rng) Is Nothing Then
        Application.EnableEvents = False
        For Each rCell In Intersect(Target, rng)
            If Len(rCell.Value) > iChars Then
                rCell.Value = Left(rCell.Value, iChars)
                MsgBox rCell.Address & " has more than" _
                  & iChars & " characters." & vbCrLf _
                  & "It has been truncated."
            End If
        Next
    End If

ExitHandler:
    Application.EnableEvents = True
    Set rCell = Nothing
    Set rng = Nothing
    Exit Sub

ErrHandler:
    MsgBox Err.Description
    Resume ExitHandler
End Sub

To use this macro, you simply need to change the value assigned to iChars (represents the maximum length allowed) and the range assigned to rng (currently set to A1:A10). Because the macro checks only for changes within the specified range, it is much faster with larger worksheets than the macro that checks all the cells used.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (3150) applies to Microsoft Excel 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Excel (Excel 2007 and later) here: Setting a Length Limit on Cells.