Hello,
Sounds like a fun project, I'd be happy to undertake it, in several steps or phases. First, I think a command-line application as a proof-of-concept prototype would be useful to verify the formula and algorithm. This could be written quickly, likely in a day or so. This prototype would also be used later in the project to verify that the "prettier" implementations are calculating the formula correctly. Next, I would write a Javascript application to run in any web browser, usable on both laptops/desktops and smartphones. Finally, Android and iOS app would be developed, to offer a better, easier to use interface on smartphone platforms.
I have nearly 50 software development experience (I started quite young), much of it in C over the years, for satellite communications systems for NASA and commercial aerospace firms. In recent years I have developed applications for web browsers using Javascript, and I have developed several Android applications.
This proposal covers development of the proof-of-concept prototype and Javascript application. I would be happy to provide a quote for the Android and iOS apps at a later time, once more of the details for those apps can be determined.
I encourage to select me to develop this software for you. I am a quick study and easy to work, and you will get software that works just how you want it to. Thank you for considering this proposal.
Jeff Spiegler