Long audible sigh here.................

One more victim of "merged cells".

It may be better to use the "Center Across Selection" from
Cells>Format>Alignment.

Wrap Text works fine on merged cells, but Autofit does not work.

You need VBA event code to do that.

Here is code from Greg Wilson.

Private Sub Worksheet_Change(ByVal Target As Range)
Dim NewRwHt As Single
Dim cWdth As Single, MrgeWdth As Single
Dim c As Range, cc As Range
Dim ma As Range

With Target
If .MergeCells And .WrapText Then
Set c = Target.Cells(1, 1)
cWdth = c.ColumnWidth
Set ma = c.MergeArea
For Each cc In ma.Cells
        MrgeWdth = MrgeWdth + cc.ColumnWidth
Next
Application.ScreenUpdating = False
    ma.MergeCells = False
     c.ColumnWidth = MrgeWdth
      c.EntireRow.AutoFit
       NewRwHt = c.RowHeight
      c.ColumnWidth = cWdth
    ma.MergeCells = True
   ma.RowHeight = NewRwHt
  cWdth = 0: MrgeWdth = 0
Application.ScreenUpdating = True
End If
End With
End Sub

This is event code.  Right-click on the sheet tab and "View Code".

Copy/paste the code into that sheet module.

Gord Dibben  MS Excel MVP

I believe that merged cells to not participate in AutoFit operations. You
might have to write a macro to copy the contents to a new, temporary
worksheet, AutoFit the cell there, measure the width of that cell, then set
the width of the cell on your original worksheet to this value.

Does this range have Wrap Text turned on? Do you want the row height to be
a multiple of the normal row height? Then you have an even more complex
problem at hand.