Using DEC2BIN() with large numbers

Question

I\'m trying to convert 4503599627370495 into binary in Excel. DEC2BIN() returns #NUM! error because DEC2BIN cannot handle such a large number.

Any thou

Answer 1

I modified AndruWitta's modification a little bit to handle negative numbers and return the binary number in two's complement format.

Function DecToBin(ByVal DecimalIn As Variant, Optional NumberOfBits As Variant) As String
  DecToBin = ""
  DecimalIn = CDec(DecimalIn)
  If DecimalIn < 0 Then
  DecimalIn = -DecimalIn - 1

     Do While DecimalIn <> 0
        DecToBin = Trim$(Str$(Not DecimalIn - 2 * (Int(DecimalIn / 2 + 1)))) & DecToBin
        DecimalIn = Int(DecimalIn / 2)
    Loop
    DecToBin = Trim$(Str$(1)) & DecToBin
  Else
    Do While DecimalIn <> 0
        DecToBin = Trim$(Str$(DecimalIn - 2 * Int(DecimalIn / 2))) & DecToBin
        DecimalIn = Int(DecimalIn / 2)
    Loop
  End If
  If Not IsMissing(NumberOfBits) Then
    If Len(DecToBin) > NumberOfBits Then
      DecToBin = "Error - Number too large for bit size"
    Else
      DecToBin = Right$(String$(NumberOfBits, "0") & _
      DecToBin, NumberOfBits)
    End If
  End If
End Function