RPN Calc 4+

James Mattis

Designed for iPad

    • 4.0 • 2 Ratings
    • $0.99


A simple RPN calculator!

A simple reverse polish notation calculator loosely based on my trusty HP-32SII that runs on iPhone, iPad, and Apple Watch!

If you are familiar with HP RPN calculators, the operation of this calculator should seem very straightforward - albeit simplified. It can't be programmed, and it doesn't handle binary, or hexadecimal numbers.

But, it has a clean, simple interface with large, easy to press buttons. It has all of the functions required for quick calculations when your iPhone is handier than your computer or calculator.

And, remember those cool calculator watches from the 1980s? Unfortunately, none of them were RPN. RPN Calc brings a reverse polish notation watch calculator to the Apple Watch!

In addition to the standard RPN Calculator app that runs on iPhone, iPad, and Apple Watch, RPN Calc includes a handy micro RPN Calc Today Extension available for convenient access to quick calculations from the pull down Today screen.

What’s New

Version 12.0.7

- Minor bug fix.

Ratings and Reviews

4.0 out of 5
2 Ratings

2 Ratings

Eyekazoo ,

Clean Design... But need one one thing

Nice layout. Works well but needs one more thing.

It is very necessary to have an x(exchange)y function on the keyboard.

Many calculations need this capability to set up for a solution as RPN uses the x-y order for them....

Please add this to an update if you can.

Arsoft1985 ,

Excellent RPN calculator

Just as advertised - very clean, simple rpn calculator. It works perfectly, beautifully designed, no crashes. It has all the functions you are likely to need for scientific calculating. The unit conversion feature (actually, quite extensive) is a very nice extra. Suggestions for updates/improvements: have the calc float over the background wallpaper rather than having a completely white background, and ability to position to calc over the background and remember its position. This would be nice when iPad allows multitasking. A row of storage registers might be nice. Maybe showing more registers than the x and y registers is something to consider, but would probaby ruin the beautiful simplicity this calculator displays.

joemeyer ,

Works well on Watch and Widget

I have always liked RPN calculators more than algebraic. This is a fairly simple RPN calculator that works surprisingly well as a widget but also on the Apple Watch. It has a four level stack. It does have an unusual behavior where if the stack is full and you add up all the numbers the number that was on the top of the stack is repeated ad infinitum in the Y position. If you pay attention to what you're doing this should not cause a problem but I found it odd. I would like to see instructions included as well as sound effects in the widget so that when I press on the key there is a click or tone.

App Privacy

The developer, James Mattis, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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