# RPNPro vs Calccis

The clearest difference is update cadence: Calccis at every 3 weeks against RPNPro's every 37 months. RPNPro's advantage is iOS requirement (9.1 vs 17.6). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

RPNPro ships an update every 37 months, Calccis every 3 weeks. The most recent releases landed on September 28, 2026 and September 12, 2026 respectively.

## The numbers

| Metric | RPNPro | Calccis |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/rpnpro/id603155368/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 37 months | **Every 3 weeks** |
| Monetization | Free | — |
| Size | 1 MB | 1 MB |
| Requires iOS | **9.1** | 17.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Felix Meier](https://appshunter.io/developer/603155771) | [Jukka Aittola](https://appshunter.io/developer/1676073314) |

## What reviewers say

### RPNPro

[App page](https://appshunter.io/ios/app/rpnpro/id603155368)

This calculator utilizes Reverse Polish Notation (RPN) for input, mirroring the functionality of classic HP calculators. It features a four-level stack with X, Y, Z, and T registers, displaying the X register in decimal, hexadecimal, and binary.

**Highlights:** Reverse Polish Notation (RPN) input, Four-level stack (X, Y, Z, T registers), Decimal, hexadecimal, and binary display, Modeled after HP calculators, Designed for software engineers

**Features:** macOS Compatibility

**In-app purchases:** none


### Calccis

[App page](https://appshunter.io/ios/app/calccis/id6446233205)

**In-app purchases:** none


## Frequently asked questions

### Is RPNPro free?

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

### Is Calccis free?

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

### Do RPNPro or Calccis have ads?

Neither RPNPro nor Calccis shows ads.

### Which is updated more often, RPNPro or Calccis?

RPNPro ships an update every 37 months, and Calccis every 3 weeks. Most recently, RPNPro was updated on September 28, 2026 and Calccis on September 12, 2026.

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