EniG. Chemistry Assistant is an expression calculator for fast calculations of the molecular weight of compounds by simple entry of chemical formula, and replaces the element symbols with their atomic weight. This program translates both texts with chemical element symbols or without them into a mathematical expressions and calculates them. The program includes functions for statistical analysis, solving of quadratic equations, physical constants, and preparing solution calculations. The element symbols can be written in lowercase letters, and the intelligent routine in the program will try to translate them and will show the result of translation - or it will report an error. The appearance of mathematical expression, which is the result of the translation, can be seen if the mouse pointer is held over the entry field. The right mouse button has several commonly used anions and molecules. Chemistry Assistant also includes a detailed help file containing syntax, usage, and examples for all of the supported functions. The calculator also provides a list of common physical constants and performs various conversions between English and metric units. Every function that is supported by Chemistry Assistant can be inserted by clicking on the button with function name or type its name on the physical keyboard. Some functions are not associated with the buttons, but every function can be called by typing its name.