Probably the best all-around best definitive tool to use to decide whether something is a "cult" or a "religion", without putting your own beliefs on the validity or invalidity of the group's belief is the Advanced Bonewitz Cult Danger Evaluation Frame (ABCDEF). http://www.neopagan.net/ABCDEF.html He has the person making the evaluation look and decide for themselves on how likely something is to be a "cult" as opposed to "group with strange/foreign beliefs". It has you evaluate how much the group controls its members - financially, practically (surrender of will/disempowerment), sexually controlling or using members, attributing special wisdom or knowledge of the will of the object of worship to its leader(s), proselytization, dropout control, how much wealth the group or its leaders have as compared to their average members, isolation from non-members, paranoia, violence, grimness, and hypocrisy.
The beauty of this is that if used at all objectively, it is utterly useless for deciding something is a cult just because it was made up a week ago last Tuesday, has 5 members and worships asphalt. It can get high marks for some of the world's popular "religions" which are in some ways very cultlike.
Weird beliefs are not necessarily cults, and large religions may well be very large cults.
The beauty of this is that if used at all objectively, it is utterly useless for deciding something is a cult just because it was made up a week ago last Tuesday, has 5 members and worships asphalt. It can get high marks for some of the world's popular "religions" which are in some ways very cultlike.
Weird beliefs are not necessarily cults, and large religions may well be very large cults.