Add 1 to font size of entire worksheet

I would suggest to set defined size and font type you need to make it all identical, example

Sub test1()
Application.ScreenUpdating = False
With ActiveSheet
    .UsedRange.Font.Size = 20
    .Name = "Arial Cyr"
End With
Application.ScreenUpdating = True
End Sub

Thanks for the response.

I believe i have it figured out.

Sub Resize_Fonts()
    With Cells
        .Font.Size = Selection.Font.Size + 1
        End With
End Sub

Thank you Roy for the input.

Along the same question, any idea why this doesnt this work?

Private Sub FontFix()
    With UsedRange.Cells
    
        ' All unlocked cells format to Shrink To Fit
        If Not Cells.Locked Then
            .ShrinkToFit = True
            End If
            
        ' All Non-Bold fonts or Non-Wingding fonts change to Arial Narrow.
        If Not .Font.Bold = True And Not Cells.Locked And Not .Font.Name = "Wingdings" Then
            .Font.Name = "Arial Narrow"
            End If
            
        ' All Wingding fonts change to bold and size 18.
        If .Font.Name = "Wingdings" Then
            .Font.Size = 18
            .Font.Bold = True
            .ShrinkToFit = False
            End If
            
    End With
End Sub

I know i have something typed incorrectly because it bypasses all the IF statements as soon as it gets to them (as if each one was false).

no object to apply, no Sheet indicated

With UsedRange.Cells

it should be for example:

With Activesheet.UsedRange.Cells

This is driving me nuts that i can't get this little thing to run right. I attached my sample file.

Thank you roy! I did change it by adding my original question to the code (i missed the +1 portion when trying to make the code do more)

I think i understand what i was missing: I basically didnt set an object to apply it to still (like waterserv mentioned) correct?

Private Sub FontFix1()
    Dim rCl As Range
    With ActiveSheet
        .Unprotect
        For Each rCl In .UsedRange.SpecialCells(xlCellTypeConstants)
            With rCl
                ' All unlocked cells format to Shrink To Fit
                If Not .Locked Then
                    .ShrinkToFit = True
                    .Font.Size = Selection.Font.Size + 1
                    End If
                ' All unlocked cells + Non-Bold fonts + Non-Wingding fonts change to Arial Narrow.
                If Not .Font.Bold = True And Not .Locked And Not .Font.Name = "Wingdings" Then .Font.Name = "Arial Narrow"
                ' All Wingding fonts change to bold and size 18.
                If .Font.Name = "Wingdings" Then
                    .Font.Size = 18
                    .Font.Bold = True
                    .ShrinkToFit = False
                End If
            End With
        Next rCl
        .Protect
    End With
End Sub