eValuator is a lightweight OS X app that be used to evaluate algebraic expressions. It allows you to combine numerous functions and up to six variables, while including the latest CODATA 2014, IAU 2012 and 2015 fundamental and astronomical constants.

The application’s layout it straightforward and consists of two main panels, one of which is designed to help with inserting expressions, although it can be disabled if you have no need of it.

eValuator can also remain on top of all other windows, to ensure it is always within reach whenever you want to perform calculations.

eValuator offers an area designed for text input, where you can write or paste algebraic expressions. They are evaluated in real-time, and the answer is displayed in a separate panel using a green or red background, depending on the expression’s validity.

You can define and work with up to six variables, and it is possible to replace them with the current answer, as well as add or subtract the obtained value.

The app allows you to switch between c.g.s and S.I. units for the available constants at any time.

eValuator includes a built-in scrapbook that can be used to store values, expressions or any other important notes. Clicking the icon located next to the answer field causes the current result and expression to be stored in the scrapbook, together with a timestamp and a list of the employed variables.

All these notes are saved automatically whenever the application is shut down, along with the current expression, answer and variables.

While eValuator is very intuitive, it is worth noting that it is also bundled with extensive documentation, providing detailed explanations for all of the app’s functions, as well helpful examples and a complete listing of all the supported constants.

Overall, eValuator is a well-designed app that has no real flaws, as it performs its intended functions without reproach. If you need an easy-to-use scientific calculation tool that can evaluate algebraic expressions, your should try it out.