This should work on any relatively recent device that has MicroPython and I guess older devices too since it uses all builtins and simple logic with the standard math library as the only import.
I wanted a portable, quick, way to calculate the KFI on my calculator. It also serves as a reference on the steps involved. It will ask for the necessary values and then output them and the derivatives Dv, Cr, and F. Included is a complimentary script that prints the information of m_divisor, asset class, and phase thresholds.
I wrote it on the Casio fx-CG100 graphing calculator, MicroPython 1.9.4.
Download (free as in beer): https://ko-fi.com/s/216efb3532