# RPN vs RLM

The clearest difference is price: RLM at Free against RPN's $1.99. RLM also leads on update cadence (monthly vs every 3 months). RPN's advantage is rating (5.0 vs 4.1) and in-app purchases (none vs 4). On ratings volume, ads and device support there is nothing between them.

RLM is free to download; RPN costs $1.99 up front. RLM sells 4 in-app purchases, starting at $0.49 per month. RPN asks for nothing beyond the download.

RPN holds the better App Store score, 5.0 against 4.1. Both are backed by a comparable volume of ratings — 8 and 18 respectively. Written reviews point the same way: 100% of RPN's written reviews are positive against 80% of RLM's.

RPN ships an update every 3 months, RLM monthly. The most recent releases landed on October 20, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | RPN | RLM |
| --- | --- | --- |
| Price | $1.99 | **Free** |
| Rating | **[5.0 (8 ratings)](https://appshunter.io/ios/app/rpn-55-sd/id1469907917/reviews)** | [4.1 (18 ratings)](https://appshunter.io/ios/app/rlm-15cx/id1636646608/reviews) |
| Number of ratings | 8 | **18** |
| Positive reviews | **100.0% of reviews** | 80.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | **Monthly** |
| Monetization | Paid | **Free with in-app purchases** |
| Size | 17 MB | 6 MB |
| Requires iOS | **12.0** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [CuVee Software](https://appshunter.io/developer/424873503) | [R.L.M. Software](https://appshunter.io/developer/289639238) |

## What reviewers say

### RPN

[App page](https://appshunter.io/ios/app/rpn-55-sd/id1469907917)

This app is a photo-realistic simulation of a classic Hewlett-Packard programmable scientific calculator from the 1970s. It includes a 100-hour digital timer, clock functions, and original HP programs.

**Highlights:** Photo-realistic look-and-feel, Programmable with conditional branching, 100-hr timer and 12/24-hr clock, Original HP programs built-in, Extended features for enhanced usability, Sharing via email, AirDrop, and more

**Features:** macOS Compatibility

**In-app purchases:** none


### RLM

[App page](https://appshunter.io/ios/app/rlm-15cx/id1636646608)

This advanced scientific calculator emulates the functionality of the HP-15C, offering comprehensive tools for finance, business, statistics, and scientific calculations. It supports programming, equation solving, and unit conversions, optimized for iOS devices.

**Highlights:** Programmable advanced scientific calculator, Finance and business calculation menus, Statistics and probability functions, Complex numbers and matrix operations, Unit and currency conversions, Equation solver and programming capabilities

**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 |
| One-Time Purchase | $9.99 | one-time |


## Frequently asked questions

### Is RPN free?

RPN costs $1.99, with no in-app purchases.

### Is RLM free?

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

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

RPN is rated higher. RPN averages 5.0 out of 5 from 8 ratings, while RLM averages 4.1 from 18 ratings.

### Do RPN or RLM have ads?

Neither RPN nor RLM shows ads.

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

RPN ships an update every 3 months, and RLM monthly. Most recently, RPN was updated on October 20, 2026 and RLM on October 24, 2026.

---

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