99% of this answer depends on your location, whether you support other individuals, and how many amenities you need. The best source of information likely comes from current/former students in the program you're thinking about attending.
I went to a school in an area with a low cost of living on a stipend of $23,000. And without anyone else to support. I lived like a king. So in my case, the answer was I didn't need any other sources of income/money.
On the other hand, if you're living in a location where you're paying huge sums of money on rent, transportation, childcare, etc. - you're going to have to make those calculations yourself.
We can debate the merits of the poverty line but that's not going to actually help you much in your own calculation.