# SigiCalc vs RPN Memory Calculator

The clearest difference is review sentiment: SigiCalc at 50% against RPN Memory Calculator's 0%. SigiCalc also leads on in-app purchases (none vs 1). RPN Memory Calculator's advantage is update cadence (every 4 months vs every 48 months) and iOS requirement (11.3 vs 17.0). On price, ads, monetization model and device support there is nothing between them.

Both are free to download. RPN Memory Calculator sells 1 one-off in-app purchase. SigiCalc asks for nothing beyond the download.

SigiCalc ships an update every 48 months, RPN Memory Calculator every 4 months. The most recent releases landed on October 27, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | SigiCalc | RPN Memory Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/sigicalc/id522503444/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | **50.0% of reviews** | 0.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 48 months | **Every 4 months** |
| Monetization | Free | Free |
| Size | 3 MB | 8 MB |
| Requires iOS | 17.0 | **11.3** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Siegware](https://appshunter.io/developer/443908611) | [Neverest Limited](https://appshunter.io/developer/1360645388) |

## What reviewers say

### SigiCalc

[App page](https://appshunter.io/ios/app/sigicalc/id522503444)

This app provides a graphical RPN calculator with an undo feature. Users can input mathematical equations and instantly visualize them with a plot. It's designed for simplicity and practicality in mathematical calculations.

**Highlights:** Graphical RPN calculator, Equation plotting, Undo functionality, Simple interface, Practical calculations

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

**In-app purchases:** none


### RPN Memory Calculator

[App page](https://appshunter.io/ios/app/rpn-memory-calculator/id1398878075)

This application provides a straightforward reverse Polish notation (RPN) calculator with essential functions and memory operations. It also includes integrated unit conversions for various measurements, allowing for quick conversions directly within the app. The calculator remembers your session, preserving all registers and memory values for future use.

**Highlights:** Reverse Polish Notation (RPN) input, Seven core calculator functions, Memory operations, Integrated unit conversions (Speed, Mass, Temperature, Pressure), Persistent state saving, Three visible registers

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Calculator Unit Conversions | $0.99 | one-time |


## Frequently asked questions

### Is SigiCalc free?

SigiCalc is free to download, with no in-app purchases.

### Is RPN Memory Calculator free?

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

### Do SigiCalc or RPN Memory Calculator have ads?

Neither SigiCalc nor RPN Memory Calculator shows ads.

### Which is updated more often, SigiCalc or RPN Memory Calculator?

SigiCalc ships an update every 48 months, and RPN Memory Calculator every 4 months. Most recently, SigiCalc was updated on October 27, 2026 and RPN Memory Calculator on October 24, 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.*