Optimizing code speed: Hiding rows with loops - looking for faster way

Try this.

Dim myRng As Range
Dim myCell As Range
Dim rngHide As Range

    If Range("B63").Value = True Then
        Set myRng = Range("C4,C5,C6,C7,C8,C9,C10,C12,C13,C14,C15,C16,C17,C18,C19,C21,C22,C23,C24,C25,C26,C28,C29,C30,C31,C32,C33,C34,C35,C37,C38,C40,C41,C42,C43,C44,C45,C46,C48,C49,C51,C52,C53,C54,C55,C56,C57,C59,C60,C61")
        For Each myCell In myRng.Cells

            If myCell.Value = "" Then
                If rngHide Is Nothing Then
                    Set rngHide = myCell
                Else
                    Set rngHide = Union(rngHide, myCell.EntireRow)
                End If
            End If
        Next myCell
    Else
        Range("C1:C65536").EntireRow.Hidden = False
    End If

    If Not rngHide Is Nothing Then

        rngHide.EntireRow.Hidden = True
    End If

My this is awesome! From 6-7 seconds to 0,1 seconds. Unbelievable. Thanks

Actually, I have another code: Its the second rowhiding and is intended to hide the capture-rows. It is essentially a similar code, but a bit different. Dont be scared by its size, its just the same 9 times for 9 rows. I didn't see a way to use the union thing, so my question is: Is there a way to optimize it? So its so super fast, too?

Sub Diätplaner_Druckansicht_erweitert()
Dim myRng As Range
Dim myCell As Range
Dim Cell1 As Range
Dim Range1 As Range
Dim Hidden1 As Boolean
Dim Cell2 As Range
Dim Range2 As Range
Dim Hidden2 As Boolean
Dim Cell3 As Range
Dim Range3 As Range
Dim Hidden3 As Boolean
Dim Cell4 As Range
Dim Range4 As Range
Dim Hidden4 As Boolean
Dim Cell5 As Range
Dim Range5 As Range
Dim Hidden5 As Boolean
Dim Cell6 As Range
Dim Range6 As Range
Dim Hidden6 As Boolean
Dim Cell7 As Range
Dim Range7 As Range
Dim Hidden7 As Boolean
Dim Cell8 As Range
Dim Range8 As Range
Dim Hidden8 As Boolean
Dim Cell9 As Range
Dim Range9 As Range
Dim Hidden9 As Boolean
        
        If Range("B64").Value = True Then
        Set Range1 = Range("C4:C10")
        For Each Cell1 In Range1.Cells
            If Cell1.EntireRow.Hidden = True Then
                Hidden1 = True
            Else: Hidden1 = False
            Exit For
            End If
        Next Cell1
        If Hidden1 = True Then Range("C3").EntireRow.Hidden = True
        
        
        Set Range2 = Range("C12:C19")
        For Each Cell2 In Range2.Cells
            If Cell2.EntireRow.Hidden = True Then
                Hidden2 = True
            Else: Hidden2 = False
            Exit For
            End If
        Next Cell2
        If Hidden2 = True Then Range("C11").EntireRow.Hidden = True
        
        Set Range3 = Range("C21:C26")
        For Each Cell3 In Range3.Cells
            If Cell3.EntireRow.Hidden = True Then
                Hidden3 = True
            Else: Hidden3 = False
            Exit For
            End If
        Next Cell3
        If Hidden3 = True Then Range("C20").EntireRow.Hidden = True

        Set Range4 = Range("C28:C35")
        For Each Cell4 In Range4.Cells
            If Cell4.EntireRow.Hidden = True Then
                Hidden4 = True
            Else: Hidden4 = False
            Exit For
            End If
        Next Cell4
        If Hidden4 = True Then Range("C27").EntireRow.Hidden = True
        
        Set Range5 = Range("C37:C38")
        For Each Cell5 In Range5.Cells
            If Cell5.EntireRow.Hidden = True Then
                Hidden5 = True
            Else: Hidden4 = False
            Exit For
            End If
        Next Cell5
        If Hidden5 = True Then Range("C36").EntireRow.Hidden = True
        
        Set Range6 = Range("C40:C46")
        For Each Cell6 In Range6.Cells
            If Cell6.EntireRow.Hidden = True Then
                Hidden6 = True
            Else: Hidden6 = False
            Exit For
            End If
        Next Cell6
        If Hidden6 = True Then Range("C39").EntireRow.Hidden = True
        
        Set Range7 = Range("C48:C49")
        For Each Cell7 In Range7.Cells
            If Cell7.EntireRow.Hidden = True Then
                Hidden7 = True
            Else: Hidden7 = False
            Exit For
            End If
        Next Cell7
        If Hidden7 = True Then Range("C47").EntireRow.Hidden = True
        
        Set Range8 = Range("C51:C57")
        For Each Cell8 In Range8.Cells
            If Cell8.EntireRow.Hidden = True Then
                Hidden8 = True
            Else: Hidden8 = False
            Exit For
            End If
        Next Cell8
        If Hidden8 = True Then Range("C50").EntireRow.Hidden = True
        
        Set Range9 = Range("C59:C61")
        For Each Cell9 In Range9.Cells
            If Cell9.EntireRow.Hidden = True Then
                Hidden9 = True
            Else: Hidden9 = False
            Exit For
            End If
        Next Cell9
        If Hidden9 = True Then Range("C58").EntireRow.Hidden = True
    Else
    Range("C3,C11,C20,C27,C39,C50,C58").EntireRow.Hidden = False
    If Range("E67").Value = "True" Then Range("C36,C47").EntireRow.Hidden = False
    End If
End Sub

bump, bc its already on the end of page 2

Application.ScreenUpdating = False & True already fixed the problem. It does essentially what I wanted, not showing the calculationstuff and needs less time. Thx!