# i41CX vs RLM

The clearest difference is price: RLM at Free against i41CX's $7.99. i41CX's advantage is rating (4.6 vs 4.1) and update cadence (every 10 days vs monthly). On ratings volume, ads, in-app purchases and monetization model there is nothing between them.

RLM is free to download; i41CX costs $7.99 up front. i41CX sells 4 one-off in-app purchases and RLM sells 4 in-app purchases, starting at $0.49 per month. Whichever you choose, the download price is not the number that matters.

i41CX holds the better App Store score, 4.6 against 4.1. Both are backed by a comparable volume of ratings — 45 and 17 respectively. Written reviews point the same way: 90% of i41CX's written reviews are positive against 80% of RLM's.

i41CX ships an update every 10 days, RLM monthly. The most recent releases landed on October 23, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | i41CX | RLM |
| --- | --- | --- |
| Price | $7.99 | **Free** |
| Rating | **[4.6 (45 ratings)](https://appshunter.io/ios/app/i41cx/id292619450/reviews)** | [4.1 (17 ratings)](https://appshunter.io/ios/app/rlm-15cx/id1636646608/reviews) |
| Number of ratings | **45** | 17 |
| Positive reviews | **90.5% of reviews** | 80.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 10 days** | Monthly |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Best chart rank | **#144** | — |
| Size | 135 MB | 6 MB |
| Requires iOS | 16.0 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Antonio Lagana](https://appshunter.io/developer/289068868) | [R.L.M. Software](https://appshunter.io/developer/289639238) |

## What reviewers say

### i41CX

[App page](https://appshunter.io/ios/app/i41cx/id292619450)

**Currently charting:** #144 Top Paid · Productivity (US App Store)

This app offers a powerful RPN scientific calculator experience, functionally equivalent to a renowned model. It provides extensive memory registers, over 300 built-in functions, and programmability. Advanced features can be unlocked via in-app purchases.

**Highlights:** RPN logic with 4-element stack, 319 main and 124 extended memory registers, Over 300 built-in functions, Programmable up to 2000 lines, User-definable keyboard, Bluetooth keyboard support, Device integration features

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Overlays Upgrade | $2.99 | one-time |
| Printer Upgrade | $3.99 | one-time |
| CAS Upgrade | $7.99 | one-time |
| i41CX+ Features Upgrade | $17.99 | one-time |


### 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 i41CX free?

i41CX costs $7.99, and also offers in-app purchases.

### Is RLM free?

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

### Which has better reviews, i41CX or RLM?

i41CX is rated higher. i41CX averages 4.6 out of 5 from 45 ratings, while RLM averages 4.1 from 17 ratings.

### Do i41CX or RLM have ads?

Neither i41CX nor RLM shows ads.

### Which is updated more often, i41CX or RLM?

i41CX ships an update every 10 days, and RLM monthly. Most recently, i41CX was updated on October 23, 2026 and RLM on October 15, 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.*