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. The calculator has an attractive user interface with large buttons, an easy to read multiline display, and support for six color themes. eCalc includes a full operational stack with a four line interactive display that supports keeping a history of all calculations (similar to a full featured handheld calculator). The user can scroll through previous calculations by using the mouse scroll wheel or associated user interface buttons. eCalc is well suited for both students and professionals across a large range of scientific and engineering disciplines. The complex math features of eCalc Scientific Calculator allow for calculations with both polar and rectangular formats which make it very useful for electrical engineering calculations. eCalc includes an integrated side palette that opens and closes to allow for additional functionality. Within the side palette is support for interactive unit conversion, a constants library, equation solver (for both linear and polynomial equations), and a base conversion utility. Calculations done in the side palette are easily pushed onto the main calculator stack for further evaluations.