QEasyCalc is a open-source calculator very fast and easy to use, a useful additional tool to perform simple as well as  trigonometric calculations.

Inspired from HP calculators, QeasyCalc runs using the Reverse Polish Notation system (RPN), in which the operators folllow the operands. For instance, to add the numbers seven and eleven, one would write "7 11 +", rather than "7+11". Intermediate results are stored into a stack, which make complex calculations more efficient and the use of brackets unnecessary. Also, the results of the calculations are easier to check.
With QEasyCalc, it is possible to perform a huge number of operations, thanks to its almost infinite stack. For more information about the Reverse
Polish Notation, please refer to wikipedia.

QEasyCalc has been designed and developed with Qt.4 and can run on Linux and Windows environments. The application can be downloaded for free on this webiste. Download

QEasyCalc is a user friendly and flexible tool. The default settings can be easily changed and the user can customize the calculator to his own preferences. The virtual keyboards can be moved to any place of the screen, and even removed if the user perfers to type in using the computer's keyboard. Depending of the number of calculations to perform, the screen can be resized to adjust the size of the stack of values to display. The page Documentation describes all the functionnalities of the calculator.
QEasyCalc - RPN Calculator - 2010