Graphmatica is a graphing program created by Keith Hertzer, a graduate of the University of California, Berkeley. It runs on Microsoft Windows.
Graphmatica is distributed free of charge for evaluation purposes. After one month, non-commercial users are asked to pay a $25 licensing fee. Other licensing plans are available for commercial users.
Graphmatica can graph Cartesian functions, relations, and inequalities, plus polar, parametric and ordinary differential equations.