RPN Calc
James Mattis
A simple reverse polish notation calculator loosely based on my trusty HP-32SII that runs on iPhone, iPad, and Apple Watch!
Download price in United States
Current observed download price for the selected storefront. Open regional pricing to compare converted prices across countries.
In-app purchases in United States
Items currently visible on Apple’s public App Store page. This may not be the complete App Store Connect catalog.
Source: Apple public App Store page · Publicly visible items only · Checked Aug 4, 2026
About RPN CalcStorefront description supplied by Apple.
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.
Frequently asked questions
Quick answers based on the latest observed App Store data.
How much does RPN Calc cost in United States?
The latest observed download price is $0.99. Open the official App Store link to confirm the current checkout price.
Does RPN Calc have in-app purchases?
Apple's public page currently shows 0 purchase items in this storefront. The public list may be incomplete.
Can the price differ by country?
Yes. App Store prices can vary by storefront, currency, taxes, and developer pricing. We currently have 1 regional observations.