iPhone Screenshots


A scientific RPN calculator inspired by traditional HP calculators but created specifically for the iPhone and iPod touch. It features a standard four level stack with multiple display options, and BCD math for accuracy. Several features provide feedback for tracking the calculator buttons with your finger on the touch screen, including an audio button click and a larger delayed "heads-up" tracking display.

• A "paper" tape records transcript for later review.
• Provides standard, scientific and engineering display format modes.
• Calculator stack and memory values are saved between uses.
• Provides ten memory storage locations with arithmetic access functions.

What’s New

Version 1.3

• Add long press on backspace to clear the x register.
• Fix math bug (e.g., tan(45)).

Ratings and Reviews

4.0 out of 5
1 Rating

1 Rating

Doc2008 ,

Pretty good

It's a lot like the free classic rpn, but looks like an iPhone app.

Don't like how the buttons switch when you hit the orange second button. Kinda near at first, but annoying.

The stack can be four lines, but the LCD stays the same size so the numbers are really tiny.

Overall a nice effort, but not too impressive.

marzzz ,

Very well done

I used HP rpn calculators back in the day, and this app does a nice job or recreating it. One hint: decreasing the display size increases the space between buttons.


Needs Work

1. Keys are too small. Need to make them bigger by reducing dead space between them.

2. Don't like how the keys invert when you push the 2nd function button.


Nick Nallick
13.3 MB

Requires iOS 8.1 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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