Halcyon Calc

This is truly one of the best. Faithful reproduction of the HP-28S, the first user RPL calculator, that keeps all the good stuff and improves on the not-so-good (the display, for example, is so much better than that on the actual calculator). Stable and well thought out, with a very polished look. The plotting capabilities are pretty amazing. Very responsive developer; helped me immediately with a workaround to a minor problem and released an update within a few days. Allows me to do anything I

I went to college in the late 80's with an HP-28S. I still have the HP calculator, and it still works; and I'd been wanting an RPN calc for the phone that was similar to that one. There are a bunch of HP-12-like apps, but this is the first one I've found that behaves similar to the 28S. Very happy with Halcyon Calc; I've been able to delete all the other RPN calculator apps that I've tried.

My HP 28S calculator (the best programmable scientific calculator ever built) is back! Thanks so much! I took a rather complicated engineering program from my 28 (which used some rather esoteric functions), laid it in, and it ran perfectly! Two thumbs WAY up! More if I had them.

Love how responsive Halcyon Software is to fixing and improving this software. My favorite change on this release is the long or 3D press to get the red shift key. My 28S still runs perfectly but the battery door is so fragile. I can use Halcyon Calc all the time.