eCalc is an easy to use scientific calculator with many advanced features including unit conversion, complex number math, equation solving, and even support for both algebraic and RPN operating modes.

Features: eCalc interface is designed to look like a scientific calculator. You can choose from one of the six color themes available with the program. The calculator can handle Trigonometry, Algebra, Scientific Math, Equation Solver, Complex Numbers, Unit Converter, Decimal to Fraction calculations. You can choose to use either the reverse Polish or the RPN and algebraic notations. The interface also uses large buttons that make the use of its functionalities quite easy. Multi-line display makes the reading of results also easy. The interface makes it easy to scroll through previous calculations as in the calculation history supported in many handheld calculators. The history is maintained in a stack and up to 4 line display keeps the data in context. You can scroll through this history by scrolling using the mouse wheel. The application can take care of many scientific and engineering solutions thereby making it suitable for students as well as practicing professionals. Electrical engineering students, for example, can use the polar and rectangular co-ordinates used extensively in their discipline. The calculator displays a side panel that adds other functionality. Interactive unit conversion, a constants library and a equation solver that can calculate linear and polynomial equations and a base conversion feature are supported in this side panel. You can push the results of these calculations on to the main calculator results stack for further use, if necessary.

There`s a Mac version of the program also available besides the Windows version.

Overall: This is a very useful program. It is as easy to use as the pocket calculator everyone is familiar with.