RPN Memory Calculator is an iOS application for iPhone and iPad.
The calculator is a simple to use reverse polish notation calculator with six functions and memory operations including a memory value display and three visible registers. This is not intended to be a full scientific function calculator, it is a handy implementation of basic calculator operations using RPN.
Version 1.2 is now released, this free new version integrates unit conversions into the calculator. The "conv" button brings up an intuitive unit conversion screen that allows you to convert the x register value between numerous types. The converted value can either be accepted back into the x register, or discarded. You can also amend the value being converted from within the conversion screen. The unit conversion screen is limited to a fixed number of free uses, after which a small in-app purchase is required.
This version also remembers your calculated numbers, including all the registers and the memory field. It also remembers your last used conversion types, so if your speed conversions are usually mph to kph, these will be preselected when you launch the conversions screen.