RionaCalc is a smal and powerful calculator that can convert units of measurement, can solve quadratic equations, find root, minimum, maximum of the function, calculate value of define integral, calculate mathematical expressions. It supports complex numbers, common fractions, time, date and user-defined variables. RionaCalc can draw 2D, 3D graphics and polar plot. Program also has built-in scripting language that gives you a possibility to write your own functions.