Right click the sheet tab and select view code. Add the following. You will
need to change the cell reference...

Private Sub Worksheet_Change(ByVal Target As Range)
If Round(Range("A1"), 3) < 0 Then MsgBox "Out of Balance"
End Sub

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HTH...

Jim Thomlinson


"Gordy99" wrote:

I have a cell that checks the vertical totals with the horizontal totals and
shows the difference if they are difference.
I would like to add a pop up message box if they are different using sheet
code.
Thanks,
Gordy