I went looking for a real PhD stipend comparator app, the kind that knows what the chemistry department at a specific university pays its third-years. What I found was mostly not that. The generic budget and salary apps were never built for this problem. They know national averages. They do not know your program. That gap is the whole game.
So instead of reviewing apps that do not exist, here is what to demand from anything that claims to compare stipends. First, real per-program data. Does it have stipend figures by program, or is it repackaging a national average with your zip code on it? If it cannot name the program, it cannot compare the program. Full stop.
Second, cost-of-living adjustment. A comparator that skips this is just a list of big numbers, and big numbers lie. The adjustment has to be local and current. A cost index from three years ago is decoration.
Third, the full package. Guaranteed years, summer funding, fees, insurance. A tool that compares stipends but ignores whether funding is guaranteed for one year or five is comparing the wrong thing. The wrong thing, confidently presented, is worse than nothing.
Fourth, export and sharing. You will want to show these numbers to your advisor, your partner, or the department you are negotiating with. Screenshots are fine. A clean export is better. Plan for the conversation, not just the comparison.
Most grad school stipend calculator tools fail the first test, because they ask you to type in your own number instead of knowing it. A cost of living adjusted stipend calculator, SaaS or spreadsheet, is only as good as its inputs. What you want is a real PhD funding comparison built on program-level data: a cost of living adjusted PhD stipend figure drawn from what programs really pay.
The honest version of this article is one line. That tool is phdstipend.fyi. Its cost-of-living-adjusted offer reports compare real program figures against real local costs, across 798 US programs. Everything else I found is a calculator wearing a database costume.