RPN-70 SD is a meticulous simulation of the vintage HP-70 financial calculator from 1974, now available on iPhone. This app faithfully replicates the HP-70, offering features like loan amortization, saving plans, depreciation, and more.

Users praise its authenticity, with one review highlighting its improved functionality and additional features compared to the original device. RPN-70 SD boasts a photo-realistic design, animated keys with adjustable click sound, and correctable number entries by swiping the display.

The app includes all functions of the HP-70, allowing for cut/copy/paste of display values, viewing stack and memory registers with a double-tap, and 10 non-volatile memory registers not present in the original device.