# Complex RPN Calculator vs ThetaCalc

The clearest difference is review sentiment: ThetaCalc at 100% against Complex RPN Calculator's 52%. ThetaCalc also leads on rating (4.3 vs 3.9). Complex RPN Calculator's advantage is ratings volume (24 vs 4). On price, update cadence, ads and in-app purchases there is nothing between them.

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

ThetaCalc holds the better App Store score, 4.3 against 3.9. That said, the two scores are not equally well evidenced: Complex RPN Calculator has 24 ratings behind it against 4, so its average is the more settled of the two. Written reviews point the same way: 52% of Complex RPN Calculator's written reviews are positive against 100% of ThetaCalc's.

Complex RPN Calculator ships an update every 5 months, ThetaCalc every 3 months. The most recent releases landed on October 21, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Complex RPN Calculator | ThetaCalc |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.9 (24 ratings)](https://appshunter.io/ios/app/complex-rpn-calculator/id291826330/reviews) | **[4.3 (4 ratings)](https://appshunter.io/ios/app/thetacalc/id1521614636/reviews)** |
| Number of ratings | **24** | 4 |
| Positive reviews | 51.7% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 3 months** |
| Monetization | Free | Free |
| Size | 1 MB | 1 MB |
| Requires iOS | **16.4** | 17.6 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [John Coddington](https://appshunter.io/developer/291826333) | [Felix Stehli](https://appshunter.io/developer/1521614638) |

## What reviewers say

### Complex RPN Calculator

[App page](https://appshunter.io/ios/app/complex-rpn-calculator/id291826330)

This scientific calculator utilizes a four-level stack and natively handles complex numbers. It allows users to input and view numbers in both polar and rectangular formats, remembering its state and offering 10 memory locations.

**Highlights:** Complex number support, Four-level stack, Polar and rectangular formats, State persistence, 10 memory locations, Scientific calculations

**Features:** macOS Compatibility

**In-app purchases:** none

**What reviewers like**

- ✅ Great RPN functionality
- ✨ Complex number support
- 🆓 Free to use
- 🚫 No ads or in-app purchases
- 💻 Works on macOS

**What reviewers complain about**

- 🎨 SwiftUI design is ugly
- 🐌 Slow keyboard response
- 🖱️ Clunky operation
- 📉 Complex number operations limited
- ⚠️ Broken on newer iOS versions (historically)

**Reported bugs**

- Mutes other apps when used
- Slow keyboard response after update
- X^3 calculation incorrect for large imaginary numbers
- App crashes on opening/button press (historical iOS 9 issues)
- App starts upside down in landscape on iPad (historical iOS 8 issue)

**Requested features**

- Turn off key click sound
- Customize number display
- See the stack
- Fix slow entry response
- Fix imaginary number calculation (X^3)


### 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 Complex RPN Calculator free?

Complex RPN Calculator 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, Complex RPN Calculator or ThetaCalc?

ThetaCalc is rated higher. Complex RPN Calculator averages 3.9 out of 5 from 24 ratings, while ThetaCalc averages 4.3 from 4 ratings.

### Do Complex RPN Calculator or ThetaCalc have ads?

Neither Complex RPN Calculator nor ThetaCalc shows ads.

### Which is updated more often, Complex RPN Calculator or ThetaCalc?

Complex RPN Calculator ships an update every 5 months, and ThetaCalc every 3 months. Most recently, Complex RPN Calculator was updated on October 21, 2026 and ThetaCalc on October 1, 2026.

---

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