# Stackis RPN vs LudyRec

The clearest difference is rating: Stackis RPN at 5.0 against LudyRec's 3.7. Stackis RPN also leads on review sentiment (100% vs 75%) and monetization model (free vs freemium). LudyRec's advantage is ratings volume (12 vs 2). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Stackis RPN sells 1 one-off in-app purchase and LudyRec sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

Stackis RPN holds the better App Store score, 5.0 against 3.7. That said, the two scores are not equally well evidenced: LudyRec has 12 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 100% of Stackis RPN's written reviews are positive against 75% of LudyRec's.

Stackis RPN ships an update every 4 days, LudyRec every 3 weeks. The most recent releases landed on November 5, 2026 and November 7, 2026 respectively.

## The numbers

| Metric | Stackis RPN | LudyRec |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/stackis-rpn/id6752929114/reviews)** | [3.7 (12 ratings)](https://appshunter.io/ios/app/ludyrec-lossless-recorder/id6760564009/reviews) |
| Number of ratings | 2 | **12** |
| Positive reviews | **100.0% of reviews** | 75.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 4 days** | Every 3 weeks |
| Monetization | **Free** | Freemium |
| Size | 10 MB | 43 MB |
| Requires iOS | 17.6 | **17.0** |
| Devices | iPhone, iPod | iPhone, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [Skimra](https://appshunter.io/developer/403502071) | [Ludy Ankas, LLC](https://appshunter.io/developer/1839727404) |

## What reviewers say

### Stackis RPN

[App page](https://appshunter.io/ios/app/stackis-rpn/id6752929114)

A calculator designed for users who prefer Reverse Polish Notation (RPN). It offers a familiar interface for RPN users and includes support for duodecimal calculations.

**Highlights:** RPN calculation style, Duodecimal (dozenal) support, Familiar interface for RPN users, Simple and pleasant user experience

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Advanced Mode | $1.99 | one-time |


### LudyRec

[App page](https://appshunter.io/ios/app/ludyrec-lossless-recorder/id6760564009)

Capture raw, uncompressed audio with this audiophile-grade recorder. It bypasses automatic processing to deliver pure signal capture, offering professional metering and multiple lossless formats. Export recordings easily to various destinations.

**Highlights:** Pure Mode for raw signal capture, Lossless recording formats (WAV, ALAC, FLAC), Professional real-time metering, Export to Files App, NAS/SMB, One-tap recording with widgets, Action Button support

**Features:** macOS Compatibility, Family Sharing, Apple Watch app, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| LudyRec Pro Lifetime | $9.99 | one-time |


## Frequently asked questions

### Is Stackis RPN free?

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

### Is LudyRec free?

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

### Which has better reviews, Stackis RPN or LudyRec?

Stackis RPN is rated higher. Stackis RPN averages 5.0 out of 5 from 2 ratings, while LudyRec averages 3.7 from 12 ratings.

### Do Stackis RPN or LudyRec have ads?

Neither Stackis RPN nor LudyRec shows ads.

### Which is updated more often, Stackis RPN or LudyRec?

Stackis RPN ships an update every 4 days, and LudyRec every 3 weeks. Most recently, Stackis RPN was updated on November 5, 2026 and LudyRec on November 7, 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.*