Khi3, developed by Joël Ollivier, is a multipurpose scientific calculator. Maybe the word “multi” is little to refer to the huge amount of different things you can do with this particular piece of software.
Each time you run the application, a language selection dialog opens allowing you to choose among the following options: French, English, German, Spanish, Portuguese, and Italian. This selection is required each time you enter, this should be improved.
What you see when you finally access the calculator is surprising: a jammed window full of different buttons and text boxes. When you finally calm down and start exploring the application, things become clearer. The left section of the window stays fixed at all times no matter what you do, and is where the actual calculator is shown. It looks pretty much the same than a regular calculator, with a display and a numeric and function keyboard.
Right below the calculator there are four buttons named Page 1, 2, 3 and 4. These buttons change the content of the rest of the window, allowing you to access to different kinds of tools. The default page is number 4. From this page you can perform some financial calculations, find out what location on France corresponds with a given Zip Code, calculate change between two currencies, and access a pretty big collection of games.
Page 1 provides tools to work with complexes numbers, lines, conics and circles, statistics, combination calculations, trigonometric functions, and equations. Page 2 provides quick buttons to obtain the length of a circumference, the area of a sphere, and prime numbers, among others. Besides, this page allows finding out physics constants of the elements. Page 3 provides tools for calendars and dates calculations. You can obtain the date corresponding to a certain week of a certain year. You can make conversions between the Gregorian calendar, the Julian calendar, and the Republican calendar. This page provides a unit converter and some tools for astronomy calculations as well.
In addition to what already has been commented, Khi3 calculator includes a whole collection of auxiliary tools, classified into the following categories: Pro, Astronomy, Geometry, Analyze, Physics/Chemistry, and Others. Just to mention some of them, it includes a Divx bitrate calculator, tools to work with simulations of the solar system, tools to calculate beams in different conditions of load, tools to make hydraulics calculations, tools to work with matrices, among other tools.