# Stackis RPN vs ContactKit

The clearest difference is price: Stackis RPN at Free against ContactKit's $0.29. ContactKit's advantage is in-app purchases (none vs 1). On ads, device support and iOS requirement there is nothing between them.

Stackis RPN is free to download; ContactKit costs $0.29 up front. Stackis RPN sells 1 one-off in-app purchase. ContactKit asks for nothing beyond the download.

## The numbers

| Metric | Stackis RPN | ContactKit |
| --- | --- | --- |
| Price | **Free** | $0.29 |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/stackis-rpn/id6752929114/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 4 days | — |
| Monetization | Free | — |
| Size | 10 MB | 6 MB |
| Requires iOS | **17.6** | 18.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Skimra](https://appshunter.io/developer/403502071) | [Halit Seyfullah Baskurt](https://appshunter.io/developer/1729090764) |

## What reviewers say

### Stackis RPN

[App page](https://appshunter.io/ios/app/stackis-rpn/id6752929114)

A calculator designed for users who prefer Reverse Polish Notation (RPN). It offers a familiar interface for RPN users and includes support for duodecimal calculations.

**Highlights:** RPN calculation style, Duodecimal (dozenal) support, Familiar interface for RPN users, Simple and pleasant user experience

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Advanced Mode | $1.99 | one-time |


### ContactKit

[App page](https://appshunter.io/ios/app/contactkit-backup-to-mail/id6759486033)

**In-app purchases:** none


## Frequently asked questions

### Is Stackis RPN free?

Stackis RPN is free to download, with in-app purchases available.

### Is ContactKit free?

ContactKit costs $0.29, with no in-app purchases.

### Do Stackis RPN or ContactKit have ads?

Neither Stackis RPN nor ContactKit shows ads.

---

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