# RPNPro vs ThetaCalc

The clearest difference is review sentiment: ThetaCalc at 100% against RPNPro's 50%. ThetaCalc also leads on update cadence (every 3 months vs every 37 months) and ratings volume (4 vs 1). RPNPro's advantage is rating (5.0 vs 4.3) and iOS requirement (9.1 vs 17.6). On price, ads, in-app purchases and monetization model there is nothing between them.

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

RPNPro holds the better App Store score, 5.0 against 4.3. Both are backed by a comparable volume of ratings — 1 and 4 respectively. Written reviews complicate that: 50% of RPNPro's written reviews are positive against 100% of ThetaCalc's, so the app with the better star average is not the one people write more warmly about.

RPNPro ships an update every 37 months, ThetaCalc every 3 months. The most recent releases landed on September 28, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | RPNPro | ThetaCalc |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/rpnpro/id603155368/reviews)** | [4.3 (4 ratings)](https://appshunter.io/ios/app/thetacalc/id1521614636/reviews) |
| Number of ratings | 1 | **4** |
| Positive reviews | 50.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 37 months | **Every 3 months** |
| Monetization | Free | 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) | [Felix Stehli](https://appshunter.io/developer/1521614638) |

## 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


### ThetaCalc

[App page](https://appshunter.io/ios/app/thetacalc/id1521614636)

This utility app provides a Reverse Polish Notation (RPN) calculator. Users can extend its functionality by programming custom functions and equations using JavaScript.

**Highlights:** Reverse Polish Notation (RPN) calculator, User-programmable functions, JavaScript equation support, Extensible functionality

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is RPNPro free?

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

### Is ThetaCalc free?

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

### Which has better reviews, RPNPro or ThetaCalc?

RPNPro is rated higher. RPNPro averages 5.0 out of 5 from 1 ratings, while ThetaCalc averages 4.3 from 4 ratings.

### Do RPNPro or ThetaCalc have ads?

Neither RPNPro nor ThetaCalc shows ads.

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

RPNPro ships an update every 37 months, and ThetaCalc every 3 months. Most recently, RPNPro was updated on September 28, 2026 and ThetaCalc on October 1, 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.*