Calcpad is a free and flexible programmable mathematical and engineering calculator that includes an HTML report generator.
CalcPad can handle real and complex numbers and custom variables with multiple parameters. It also has a built-in library with standard math functions, modules, macros, string variables, and many other high-end features.
CalcPad includes built-in support for HTML, CSS commenting function putting, and SVG drawings, allowing for professional-looking reports that can be saved as HTML, .doc, or PDF formats.
CalpPad's interface has an input window to the left and an output window to the right. Fortunately, the output windows offer a help file before calculations, which makes getting started much more straightforward.
You will need Microsoft .NET installed to run the program.
Free42 HP-42S Calculator Simulator is an Open Source recreation of the HP-42S Scientific Programmable Calculator and HP-82240 Printer. Plus42 is also available.