Hello elmnas,
Not knowing the content of the cells
Option Explicit
Sub Test()
Dim myStrArray As Variant
Dim Col As String
Dim xRow As Long
Dim Result As Double
Dim iCount As Long
myStrArray = Array("N", "O", "P", "R", "S", "T", , "U", "V", "W", "X", "Y")
For iCount = LBound(myStrArray) To UBound(myStrArray)
If Not IsError(myStrArray(iCount)) Then
For xRow = 2 To ActiveSheet.Cells(Rows.Count, myStrArray(iCount)).End(xlUp).Row
Result = Result + IIf(IsNumeric(Cells(xRow, myStrArray(iCount)).Value), Cells(xRow, myStrArray(iCount)).Value, 0)
Next xRow
End If
Next iCount
MsgBox Result
End Sub