# RPN Anywhere — Bring RPN Calculator Anywhere

> Reverse Polish Notation (RPN) calculator for iPhone and Apple Watch. (iPhone/iPad app by Hiroki Kawakami.)

- Source: https://appshunter.io/ios/app/rpn-anywhere/id1250545319 (this page in markdown: same URL + `.md`)
- Developer: [Hiroki Kawakami](https://appshunter.io/developer/1221246368)
- Category: Utilities, Productivity
- Price: $0.99
- Rating: 4.46/5 from 28 App Store ratings · 18 written reviews indexed
- Age rating: 4+
- Requires: iOS 14.2 · 4 MB
- Languages: English, French, German, Japanese, Korean, Chinese, Spanish
- Released: 2017-10-06
- Data updated: 2026-06-10
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/rpn-anywhere/id1250545319/reviews.md

## What is RPN Anywhere?

This is a simple RPN Calculator which can use on iPhone and Apple Watch.

*** Important! ***
This calculator uses reverse Polish notation for input, and the operation method is different from a normal calculator using infix notation.
If you don't know about RPN Calculator, you should not purchase this app.

How to use
- All devices
> Green up-arrow is ENTER button
> Stack size can be changed at Setting Screen
> Settings button is gear icon in keypad
> Can change number format from Settings.

- iPhone / iPad
> Stack view is scrollable and can show all values in the stack
> To delete a value in the stack, swipe left on the value in stack view and tap Delete button.
> To delete last typed digit, swipe right on stack view
> Swipe action can be modified at Settings Screen
> Programs trace key operations registered in Program Settings Screen
> Setting button is replaced as other actions button while editing programs

- Apple Watch
> To show values in stack, swipe down on anywhere on the screen
> To back to main screen from stack view, swipe up on the screen
> To show scientific operators, swipe up on the screen
> To back to main screen from operators screen, swipe down on the screen
> Stack view and program view is scrollable with digital crown
> To delete last typed digit, swipe right on anywhere at Main screen
> Program view shows all programs registered in iPhone. you can't register new program on Apple Watch

## Key features

- Reverse Polish Notation (RPN) input
- iPhone and Apple Watch compatibility
- Customizable stack size
- Adjustable number formats
- Configurable swipe actions
- Program tracing

## Recent user reviews (10 of 18)

All indexed reviews: https://appshunter.io/ios/app/rpn-anywhere/id1250545319/reviews.md

### 5/5 — 小学生でも使えるRPN計算機

*2025-10-20, version 5.1*

大変使いやすいRPN計算機で、小学生の子供も、１度使ったら、この計算機以外は使いたがらないようです。
やり方がわかっていないのかもですが、iPhone, iPadで使用しているときに、スワイプ入力などで、”一つ前の計算に戻る・取り消し”処理が行えないのが残念です。

### 5/5 — RPN計算機の中で一番のおすすめ

*2025-10-03, version 5.1*

表示がシンプルで見やすいです。RPN操作に必要最小限のボタンが用意されていて、使いやすいです。それでいて「科学計算」モードに切り替えると、多数の関数が使えるようになります。さらには、プログラミング電卓の機能もあります。RPN計算機アプリは多数試しましたが、これが一番良いです。「カッコが使えない」という他の方の評価がありますが、RPN計算機に対してそれは褒め言葉だと思います。

### 4/5 — Almost perfect

*2025-07-31*

This is by far the best Apple Watch calculator app, period. 
Unfortunately there seems to be a bug where the programs you create on the iPhone do not sync to the watch. 
Even with this bug, this is still well worth buying over the Lite version of this app.

### 3/5 — Functional, but UX desperately needs work on WatchOS

*2024-11-07*

Functionally, this is a pretty competent RPN calculator. The design isn't trying to directly copy an old HP interface and it's the better for it. On iOS, that's essentially the end of the story. It works.
On WatchOS, the user interface design has a number of major inconsistencies with standard UI patterns:

The watch app is organized as a single screen with two trays at the top and bottom. The trays are accessed exclusively via touch. The stack is in the top tray and advanced functions are in the bottom tray. This is quite different from most software for the Watch, which generally use sliding cards to access things which don't fit on one screen.

The lower tray, sensibly enough, is accessed by swiping upwards anywhere on the bottom edge of the display and dismissed by swiping downwards.

The upper tray, on the other hand, is accessed by swiping down from the right half of the top edge of the display. There does not appear to be any function assigned to the left half of the display. The tray is dismissed by swiping upwards, but a full row of space in the stack is dedicated to a large "back" button which duplicates this for no discernible reason.

This arrangement simply isn't very good. Every Watch includes a hardware control for vertical movement and it's not used in any way despite the use of vertical movement for navigation. The touch controls are implemented strangely. The end result feels very non-native, is fiddly to use, and generally lacks polish.

### 5/5 — Great calculator!

*2024-11-02*

This is a great RPN calculator. I use it regularly on my Mac. 
Please update the Mac app so that it saves the *size* of the window. I have to make it larger every time I open the app.

### 5/5 — Visualising the stack

*2024-09-24*

How can we do it?

### 5/5 — The best

*2024-05-30*

The best!!!

### 4/5 — Great app if you prefer R.P.N. But…

*2023-01-06*

Have been using this app for several years and it is my go to calculator.  But one thing is missing. Can you please add a number storage for number recall?  Like a memory 1 and Memory 2 button.  The stack is great not often I want to perform several different operations on the same number.

### 4/5 — Bugs

*2022-09-17*

Copy accumulator (X) doesn’t seem to work. V5.1, Ios 15.5, iPhone 8 Copy All doesn’t seem to work Cut will delete, but doesn’t put the number on the clipboard Paste doesn’t seem to work

### 4/5 — Great RPN Calculator!

*2022-06-10*

If you're looking for a simple RPN calc that features keyboard input that makes sense (and/of is customizable) compared to the default calculator (in RPN mode) then get this calc.
The only things I wish it had are a few more GUI keys. An EE key in "basic" mode would be nice, and more stack control keys (Roll up/down, Drop) in both modes for when you want to be lazy and only use the mouse. The "scientific" mode already features an EE key and thanks to the programming function I added the stack control keys as programs. Programs appear as keys below the display starting at the left, I added a couple blank programs with spaces for titles to move my stack control keys above the numeric keys. It's almost perfect!

## Frequently asked questions about RPN Anywhere

### What is RPN Anywhere?

RPN Anywhere is a paid utility app that functions as a Reverse Polish Notation (RPN) calculator. It is compatible with iPhone, iPad, iPod, and Apple Watch, offering a unique input method for calculations.

### How does RPN Anywhere work?

RPN Anywhere uses reverse Polish notation for input, meaning numbers are entered first, followed by the operation. The 'ENTER' button is represented by a green up-arrow, and users can adjust stack sizes and number formats in the settings.

### Is RPN Anywhere suitable for beginners?

No, RPN Anywhere is specifically designed for users who already understand and prefer Reverse Polish Notation. If you are unfamiliar with RPN, it is recommended not to purchase this app as the operation method differs from standard infix calculators.

### What devices does RPN Anywhere support?

RPN Anywhere supports a wide range of Apple devices, including iPhone, iPad, iPod, and Apple Watch. It also lists 'mac' as a supported device, though specific functionality on macOS may vary.

### How do I delete a value in the stack on RPN Anywhere?

On iPhone and iPad, you can delete a value in the stack by swiping left on the value and tapping the 'Delete' button. To delete the last typed digit, swipe right on the stack view.

### Can I create programs on the Apple Watch version of RPN Anywhere?

No, you cannot register new programs directly on the Apple Watch version of RPN Anywhere. The program view on the watch displays programs registered on the paired iPhone, but program creation is limited to the iPhone/iPad interface.

### What is the update frequency for RPN Anywhere?

RPN Anywhere was last updated on June 9, 2021, with version 5.1. The initial release date was October 6, 2017. Users can expect updates to maintain compatibility and potentially add features over time.

### What are the pricing details for RPN Anywhere?

RPN Anywhere is a paid application priced at $0.99. There are no in-app purchases or advertisements mentioned, indicating a one-time purchase for the full functionality.

## Version history (last 5 releases)

### 5.1 — 2021-06-09

Support customizing number format.

### 4.0 — 2021-01-27

Update decimal library.
Improve haptic feedback.

### 3.4 — 2020-05-03

Trigonometric function bug fix.

### 3.3 — 2020-03-26

Bug fix.

### 3.2 — 2019-11-01

Bug fix

## Apps similar to RPN Anywhere

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [RPN-25 CE](https://appshunter.io/ios/app/rpn-25-ce/id1529311398) | 4.6 (9) | $2.99 | Utilities |
| [RPN-67 SD](https://appshunter.io/ios/app/rpn-67-sd/id1109722386) | 4.6 (16) | $3.99 | Utilities |
| [CalCollections](https://appshunter.io/ios/app/calcollections/id6746972417) | — | Free | Utilities |
| [SwiftRPN](https://appshunter.io/ios/app/swiftrpn/id6470951024) | — | Free | Utilities |
| [GO-25 SciRPN](https://appshunter.io/ios/app/go-25-scirpn/id408249517) | 4.7 (23) | $4.99 | Utilities |
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## More apps by Hiroki Kawakami

- [カウントダウン時間割](https://appshunter.io/ios/app/id1221246369)
- [Multiple Countdown Timer](https://appshunter.io/ios/app/multiple-countdown-timer/id1227286814)
- [RPN Anywhere Lite](https://appshunter.io/ios/app/rpn-anywhere-lite/id1317843090)
- [Documents Previewer](https://appshunter.io/ios/app/documents-previewer/id1349722611)
- [Synchronized Stopwatch](https://appshunter.io/ios/app/synchronized-stopwatch/id1441034919)

All apps by Hiroki Kawakami: https://appshunter.io/developer/1221246368

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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 2026-06-10.*