RPN 28x Calc is a programmable scientific calculator with a pleasingly classic look. Despite its nostalgic appearance, it offers a modern and intuitive user experience, allowing you to interact with your operands by touching them in the display.

It is a reverse-polish notation (RPN) calculator with a dynamic stack display. As you add more values to the stack, the display shown on an iPad automatically expands. To see more lines, simply swipe to scroll. You can also re-order the levels or modify any of the values on the stack.


"It’s the third RPN calculator I buy for my iPad 2 and the first that makes me happy. It’s graphically appealing, intuitive and very responsive. I rated it 5 stars."
(Nuno Gomes)


Advanced commands are available in a secondary panel on iPad or as alternative button pages on iPhone. The buttons are efficiently grouped into four pages that you can quickly access by swiping left or right:

- letters A-Z for typing,
- trigonometric, logarithmic, and data manipulation commands,
- statistics, storage and programming commands
- binary numbers, system flags and boolean logic.

This is why RPN 28x Calc is unique in its class:

- You can tap a row to select it and issue commands for the selected level.
- In REORD mode, it is possible to rearrange the operands by dragging the rows.
- You can swipe up or down the display to see all levels.
- When you enter a value, you can tap a digit to reposition the cursor.
- Tap on the status indicators in the top of the display to change their state.

Additionally, on iPad:

- The display automatically resizes to show more than just 4 levels of the stack.
- You can slide the secondary panel out of view or swipe across the panel
to navigate between button pages.
- You can browse all variables and your command history in a separate viewer.
- Select a variable in the viewer to make it available as an argument to
variable-related commands in the calculator.
- Double-tap a variable in the viewer to edit it.
- Double-tap an entry in the command log to place it back onto the stack.


- Dark Appearance for ipadOS 13 or iOS 13.
- Alternative, dark app icon.
- Haptic feedback on iPhone.

RPN 28x Calc is all you need.

- High precision arithmetics.
- Supports multiple data types: real numbers, binary numbers, lists, arrays
or vectors, matrices, programs, names, and strings.
- Name your own variables; inspect them in the variable viewer.
- Use the rich command set to write your own programs.
- View the command history and the results in the log viewer.
- Customizable button click & alert volumes.
- Use the same app on iPad or iPhone.
- Use the calculator in iPad multitasking, i.e. in a Slide Over view or in Split View.
- Support for landscape orientation.
- External keyboard support.
- No ads, no tracking, and no rating requests.
- Downloadable user guide with introduction and command reference (PDF).


Plans for future versions (NOT YET SUPPORTED):
- User-definable buttons.
- Complex numbers.
- Arithmetic expressions.

What’s New

Version 3.2

- Eliminates animation conflicts which had caused sluggish button responses.
- The assistant window can now make better use of the available space on large iPads.
- Uses high-precision power function to calculate powers with integer exponents.
- Makes the busy spinner appear white in dark mode.
- Removes the obsolete "Animate All Buttons" setting with which button animations could be disabled.
- Tapping to reposition the cursor in the entry field no longer competes with lingering scroll indicators.
- Corrects selection when finishing editing an entry from a lower stack level.


Eric Roller
2.7 MB

Requires iOS 12.4 or later. Compatible with iPhone, iPad and iPod touch.



Age Rating
4,49 €


  • Family Sharing

    Up to six family members will be able to use this app with Family Sharing enabled.

More By This Developer

You May Also Like