# RPN vs O'der stack

The clearest difference is in-app purchases: RPN at none against O'der stack's 3. RPN also leads on iOS requirement (12.0 vs 15.6). O'der stack's advantage is device support (3 vs 1). On price, update cadence and ads there is nothing between them.

Both are free to download. O'der stack sells 3 one-off in-app purchases. RPN asks for nothing beyond the download.

RPN ships an update every 5 months, O'der stack every 3 months. The most recent releases landed on November 1, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | RPN | O'der stack |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.0 (4 ratings)](https://appshunter.io/ios/app/rpn-67-np/id603100249/reviews)** | — |
| Number of ratings | **4** | — |
| Positive reviews | 83.3% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 3 months** |
| Monetization | Free | — |
| Size | 38 MB | 59 MB |
| Requires iOS | **12.0** | 15.6 |
| Devices | iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [CuVee Software](https://appshunter.io/developer/424873503) | [ICT Fractal Inc.](https://appshunter.io/developer/473613262) |

## What reviewers say

### RPN

[App page](https://appshunter.io/ios/app/rpn-67-np/id603100249)

This app simulates a legendary vintage scientific calculator, offering a "live" display of its internal states and a virtual paper tape printer. It allows loading and running original sample programs, with advanced features that can be switched off for an authentic experience.

**Highlights:** Live display of stack and registers, Virtual paper tape printer, Email or print paper tape, Cut/copy/paste display value, 30 selectable background images, Non-volatile memory

**Features:** macOS Compatibility

**In-app purchases:** none


### O'der stack

[App page](https://appshunter.io/ios/app/oder-stack/id1449798272)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Free trial for 7 days. | Free | one-time |
| Activate for 1 month. | $0.99 | one-time |
| Activate for year. | $9.99 | one-time |


## Frequently asked questions

### Is RPN free?

RPN is free to download, with no in-app purchases.

### Is O'der stack free?

O'der stack is free to download, with in-app purchases available.

### Do RPN or O'der stack have ads?

Neither RPN nor O'der stack shows ads.

### Which is updated more often, RPN or O'der stack?

RPN ships an update every 5 months, and O'der stack every 3 months. Most recently, RPN was updated on November 1, 2026 and O'der stack on October 25, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*