Binaryworld - Any2Dec - Convert from any numeric base to decimal ... [ VB -> Math ]

' convert from any base to decimal
' BASE can be in the range 2-36

Function Any2Dec(ByVal otherBaseNumber As String, ByVal base As Integer) As Long
  Dim index As Long
  Dim digits As String
  Dim digitValue As Long

  ' check base
  If base < 2 Or base > 36 Then Err.Raise 5
  ' get the list of valid digits
  digits = Left("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ", base)

  ' convert to decimal
  For index = 1 To Len(otherBaseNumber)
    ' get the digit's value
    digitValue = InStr(1, digits, Mid$(otherBaseNumber, index, 1), _
      vbTextCompare) - 1
    ' error if invalid digit
    If digitValue < 0 Then Err.Raise 5
    ' add to running result
    Any2Dec = Any2Dec * base + digitValue
  Next

End Function