Correct me if I'm wrong. But from what I tested you get $0 unless the IPO/sell is over $40M. No matter if Seed or Series C or how much of the company you own.
Typical grants for post-series A employees (the 10 to 50 first employees) are at least 10X more than that. With that calculator, you get something (~ $20K) for a $40M exit. Not 0. Not amazing either.
This was one of the places where the model could be a lot more accurate, but at the cost of much more complicated math.
(Exit Price < Money Raised) ? $0
And the site is assuming the company raised $41M in funding.