# RPN — Reverse Polish Notation

> Reverse Polish Notation (iPhone/iPad app by Joachim Seland Graff.)

- Source: https://appshunter.io/ios/app/rpn/id6754224532 (this page in markdown: same URL + `.md`)
- Developer: [Joachim Seland Graff](https://appshunter.io/developer/1845679029)
- Category: Utilities, Education
- Price: Free
- Age rating: 4+
- Requires: iOS 15.6 · 1 MB
- Languages: American English
- Released: 2025-10-20
- Data updated: 2026-06-07
- User reviews in markdown: https://appshunter.io/ios/app/rpn/id6754224532/reviews.md

## What is RPN?

This is a calculator app using Reversed Polish Notation (RPN)

In Portrait mode, this app provides a basic calculator with the four arithmetic disciplines +, -, x, and /.
In Landscape mode, 30 extra buttons are available providing most functions found on a scientific calculator. You can do trigonometry, logarithms, roots, probability, and more.

RPN is neat because you can do fancy calculations without having to worry about parenthesis. Putting the operator after the operands allow the operator to infer which are its operands without the clarification offered by paranthesis.

The built-in help function (?) provides a short description of each function.

The settings page allows you to set the number format, number of decimals displayed, decimal separator and more.


## Version history (last 2 releases)

### 1.1 — 2026-01-23

Bugfixes:
- Fixed a bug causing suboptimal user interface when activating the "Button Shapes/Show Borders" accessibility setting.
- Fixed a bug causing low contrast on some text in dark mode.

### 1.0 — 2025-10-21

No release notes.

## Apps similar to RPN

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Date & Time Calculator Counter](https://appshunter.io/ios/app/date-and-time-calculator-counter/id1547673028) | 4.5 (21) | Free | Utilities |
| [Stackis RPN](https://appshunter.io/ios/app/stackis-rpn/id6752929114) | 5.0 (2) | Free | Utilities |
| [Calculator Express with Notes](https://appshunter.io/ios/app/calculator-express-with-notes/id1604079825) | 4.4 (43) | Free | Utilities |
| [Calc Pro - The Top Calculator](https://appshunter.io/ios/app/calc-pro-the-top-calculator/id438580059) | 4.7 (354) | $7.99 | Utilities |
| [Pupillary Distance Measure X](https://appshunter.io/ios/app/pupillary-distance-measure-x/id1501962819) | 4.5 (163) | $1.99 | Utilities |
| [TimeWave: Timer Chains](https://appshunter.io/ios/app/timewave-timer-chains/id1524345488) | 4.6 (23) | Free | Utilities |

## More apps by Joachim Seland Graff

- [Mathulator](https://appshunter.io/ios/app/mathulator/id6753913769)
- [KnitStitch](https://appshunter.io/ios/app/knitstitch/id6755937499)

All apps by Joachim Seland Graff: https://appshunter.io/developer/1845679029

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-07.*