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

This function will convert as big as a Double can hold. I didn't try it with negative values, though.

Function cn(ByVal n As Double, ByVal s As Double)
  'n the number to convert
  's the numberic system to convert to.
  'This function can convert to binary all the way to the length of the
  'digits string and all in between.

  Dim x As Double  'The exponent without decimals
  Dim xx As Double 'The exponent with decimals, if any
  Dim r As String  'The return string
  Dim p As Integer 'Posistion of the digit in the return string
  Dim L As Long    'Length of the string return string
  Dim d            '(d+1) because mid() does not accept 0.
                   'The position of the digit in the digits string.
 Dim v As Double   'The numeric value of the position 
                   'of the digit in the return string
  Dim digits As String
  digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
Start:

  If n > 0 Then
     xx = Log(n) / Log(s)
     x = Int(xx)
  End If
  p = x + 1
  If r = "" Then
    r = String(p, "0")
    L = p
  End If
  v = s ^ x
  d = n \ v
  Mid(r, L - x, 1) = Mid(digits, d + 1, 1)
  n = n - (v * d)
  If n <> 0 Then GoTo Start
  cn = r
End Function