# Complex RPN Calculator vs RLM

The clearest difference is rating: Complex RPN Calculator at 3.8 against RLM's 3.1. Complex RPN Calculator also leads on in-app purchases (none vs 4) and ratings volume (22 vs 7). RLM's advantage is update cadence (every 5 weeks vs every 5 months) and review sentiment (67% vs 52%). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. RLM sells 4 in-app purchases, starting at $0.49 per month. Complex RPN Calculator asks for nothing beyond the download.

Complex RPN Calculator holds the better App Store score, 3.8 against 3.1. Both are backed by a comparable volume of ratings — 22 and 7 respectively. Written reviews complicate that: 52% of Complex RPN Calculator's written reviews are positive against 67% of RLM's, so the app with the better star average is not the one people write more warmly about.

Complex RPN Calculator ships an update every 5 months, RLM every 5 weeks. The most recent releases landed on August 23, 2026 and September 10, 2026 respectively.

## The numbers

| Metric | Complex RPN Calculator | RLM |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.8 (22 ratings)](https://appshunter.io/ios/app/complex-rpn-calculator/id291826330/reviews)** | [3.1 (7 ratings)](https://appshunter.io/ios/app/rlm-11cx/id1630739014/reviews) |
| Number of ratings | **22** | 7 |
| Positive reviews | 51.7% of reviews | **66.7% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 5 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 1 MB | 6 MB |
| Requires iOS | 16.4 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [John Coddington](https://appshunter.io/developer/291826333) | [R.L.M. Software](https://appshunter.io/developer/289639238) |

## 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)


### RLM

[App page](https://appshunter.io/ios/app/rlm-11cx/id1630739014)

This app is a scientific and programmable calculator designed for science and engineering, replicating the functionality of the HP-11C. It offers extensive features for finance, business, statistics, complex numbers, and unit conversions, with a programmable interface for custom calculations.

**Highlights:** Finance calculations (amortization, bond price, Black-Scholes), Business functions (break-even, currency exchange), Statistical analysis (regression, probability distributions), Scientific functions (complex numbers, logarithms, trigonometry), Unit and currency conversions, Programmable interface for custom scripts, Equation solver

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Subscription | $0.49 | per month |
| Semi-Annual Subscription | $2.99 | per 6 months |
| Annual Subscription | $5.99 | per year |
| Lifetime Purchase | $9.99 | one-time |


## Frequently asked questions

### Is Complex RPN Calculator free?

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

### Is RLM free?

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

### Which has better reviews, Complex RPN Calculator or RLM?

Complex RPN Calculator is rated higher. Complex RPN Calculator averages 3.8 out of 5 from 22 ratings, while RLM averages 3.1 from 7 ratings.

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

Neither Complex RPN Calculator nor RLM shows ads.

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

Complex RPN Calculator ships an update every 5 months, and RLM every 5 weeks. Most recently, Complex RPN Calculator was updated on August 23, 2026 and RLM on September 10, 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.*