Last Cell of a range
    Dim Calc As Worksheet
    Dim intervalo As Range
    Dim matriz As Variant
    Dim i As Long, j As Long
    Set Calc = ThisWorkbook.Worksheets("Cálculos")
    Set intervalo = Calc.Range("A20:C30")
    matriz = intervalo
    For j = intervalo.Columns.Count To 1 Step -1
        For i = intervalo.Rows.Count To 1 Step -1
            If matriz(i, j) <> "" Then
                MsgBox intervalo(i, j).Address
                GoTo sairLoop
            End If
        Next i
    Next j
sairLoop:
Last Row of a Range in a Column
For example from A10 to A30 range if it is only filled up to A26, it will return 26:
Dim Calc As Worksheet
Dim UltimaLinha As Long
Set Calc = ThisWorkbook.Worksheets("Cálculos")
With Calc.Range("A10:A30").CurrentRegion
     UltimaLinha = .Rows(.Rows.Count).Row
End With
Last Row of a Column
To find the last line, there are several ways, but the one that I most use is:
UltimaLinha= Worksheets("Cálculos").Cells(Worksheets("Cálculos").Rows.Count, "B").End(xlUp).Row
or
Dim Calc As Worksheet
Set Calc = ThisWorkbook.Worksheets("Cálculos")
With Calc
    UltimaLinha= .Cells(.Rows.Count, "B").End(xlUp).Row
End With
or
Dim Calc As Worksheet
Set Calc = ThisWorkbook.Worksheets("Cálculos")
UltimaLinha= Calc.Cells(Calc.Rows.Count, "B").End(xlUp).Row
Last Line of the Spreadsheet
Dim ws As Worksheet
Set ws = ThisWorkbook.Worksheets("Planilha1")
lngLstRow = ws.UsedRange.Rows.Count
Upshot:
Then the line in your code would change to:
Worksheets("Cálculos").Cells(UltimaLinha, 2).Offset(1, 0).PasteSpecial xlPasteValues
or
Worksheets("Cálculos").Cells(UltimaLinha + 1, 2).PasteSpecial xlPasteValues
Observing: Declare the Ultimaline as Long (Dim UltimaLinha As Long), because many old tutorials use Integer, which has 2 bytes and
  the range from   -32 768 to 32 767. So if the Excel version is
  longer than 2007, the program will stop after line 32767. Long
  has 4 bytes and a range of -2 147 483 648 to 2 147 486 647. Where the
  Excel has a limit of 1 048 576 lines.