Add sumifs function to VBA

Question

My current excel workbook consists of stock trading data which is entered into the file at the end of each day. Each day's trading activity is put onto its own individual worksheet, and the columns table layout remain consistent throughout as its the same data fields being entered every day. My current VBA provides a sum total of certain columns on all worksheets when activated and sends the active worksheet out in an email.

However, I currently have to do a manual sumif input to sum certain data points from certain columns at the end of each day. Is there a way to incorporate the sumifs formula into vba? I have no idea how to approach this but it would be an incredibly useful tool. My macro is included below, and any suggestions guidance on how to do this would be greatly appreciated.

Sub AutoSum()
Dim wscount As Long
Dim i As Long
     wscount = ActiveWorkbook.Worksheets.Count
 For i = 1 To wscount
Sheets(i).Select
Range("K4").Select
 Selection.End(xlDown).Select
ActiveCell.Offset(2, 0).Select
Dim cel1 As String, cel2 As String
cel1 = ActiveCell.Offset(-2, 0).End(xlUp).Address
cel2 = ActiveCell.Offset(-1).Address
ActiveCell.Value = "=sum(" & (cel1) & ":" & (cel2) & ")"
Next i


'For Tips see: http://www.rondebruin.nl/win/winmail/Outlook/tips.htm
'Don't forget to copy the function RangetoHTML in the module.
'Working in Excel 2000-2016
    Dim rng As Range
    Dim OutApp As Object
    Dim OutMail As Object

    Set rng = Nothing
    On Error Resume Next
    'Only the visible cells in the selection
    Set rng = Selection.SpecialCells(xlCellTypeVisible)
    'You can also use a fixed range if you want
    'Set rng = Sheets("YourSheet").Range("D4:D12").SpecialCells(xlCellTypeVisible)
    On Error GoTo 0

    If rng Is Nothing Then
        MsgBox "The selection is not a range or the sheet is protected" & _
               vbNewLine & "please correct and try again.", vbOKOnly
        Exit Sub
    End If

    With Application
        .EnableEvents = False
        .ScreenUpdating = False
    End With

    Set OutApp = CreateObject("Outlook.Application")
    Set OutMail = OutApp.CreateItem(0)

    On Error Resume Next
    With OutMail
        .To = "nabil.hure@dnb.no"
        .CC = ""
        .BCC = ""
        .Subject = "Today's Trades" & Date
        .HTMLBody = RangetoHTML(rng)
        .Send   'or use .Display
    End With
    On Error GoTo 0

    With Application
        .EnableEvents = True
        .ScreenUpdating = True
    End With

    Set OutMail = Nothing
    Set OutApp = Nothing
End Sub


Function RangetoHTML(rng As Range)
' Changed by Ron de Bruin 28-Oct-2006
' Working in Office 2000-2016
    Dim fso As Object
    Dim ts As Object
    Dim TempFile As String
    Dim TempWB As Workbook

    TempFile = Environ$("temp") & "\" & Format(Now, "dd-mm-yy h-mm-ss") & ".htm"

    'Copy the range and create a new workbook to past the data in
    rng.Copy
    Set TempWB = Workbooks.Add(1)
    With TempWB.Sheets(1)
        .Cells(1).PasteSpecial Paste:=8
        .Cells(1).PasteSpecial xlPasteValues, , False, False
        .Cells(1).PasteSpecial xlPasteFormats, , False, False
        .Cells(1).Select
        Application.CutCopyMode = False
        On Error Resume Next
        .DrawingObjects.Visible = True
        .DrawingObjects.Delete
        On Error GoTo 0
    End With

    'Publish the sheet to a htm file
    With TempWB.PublishObjects.Add( _
         SourceType:=xlSourceRange, _
         Filename:=TempFile, _
         Sheet:=TempWB.Sheets(1).Name, _
         source:=TempWB.Sheets(1).UsedRange.Address, _
         HtmlType:=xlHtmlStatic)
        .Publish (True)
    End With

    'Read all data from the htm file into RangetoHTML
    Set fso = CreateObject("Scripting.FileSystemObject")
    Set ts = fso.GetFile(TempFile).OpenAsTextStream(1, -2)
    RangetoHTML = ts.readall
    ts.Close
    RangetoHTML = Replace(RangetoHTML, "align=center x:publishsource=", _
                          "align=left x:publishsource=")

    'Close TempWB
    TempWB.Close savechanges:=False