Handy Calculator is a simple Mac application that comes in handy when you wish to make basic calculations on your computer. The program provides you with a nicely-designed and user-friendly interface, immediately offers you the results you need, and allows you to copy your results to a clipboard.
The app's main window is entirely black - except for the C button which is red. Once you click outside the program's interface, it becomes 80% transparent.
Another thing I like is that the utility takes a very small amount of time to offer you the results.
However, the application only allows you to make basic math calculations (addition, subtraction, multiplication, and division). Hence, you don't have access to trigonometry or geometry symbols to use on your calculations.
To sum things up, I don't think it's worth installing a third-party application to complete tasks that can easily be finalized by Mac's default Calculator tool, especially since this program offers a limited amount of useful features.