# Janus Calculator vs RPN

The clearest difference is price: Janus Calculator at Free against RPN's $1.99. RPN's advantage is rating (4.3 vs 2.0) and update cadence (every 4 months vs every 45 months). On review sentiment, ads, in-app purchases and device support there is nothing between them.

Janus Calculator is free to download; RPN costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

RPN holds the better App Store score, 4.3 against 2.0. That said, the two scores are not equally well evidenced: RPN has 15 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 83% of Janus Calculator's written reviews are positive against 82% of RPN's, so the app with the better star average is not the one people write more warmly about.

Janus Calculator ships an update every 45 months, RPN every 4 months. Both last shipped on November 1, 2026.

## The numbers

| Metric | Janus Calculator | RPN |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Rating | [2.0 (1 ratings)](https://appshunter.io/ios/app/janus-calculator/id373378721/reviews) | **[4.3 (15 ratings)](https://appshunter.io/ios/app/rpn-45-sd/id509923051/reviews)** |
| Number of ratings | 1 | **15** |
| Positive reviews | **83.3% of reviews** | 81.8% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 45 months | **Every 4 months** |
| Monetization | **Free** | Paid |
| Size | 1 MB | 14 MB |
| Requires iOS | 26.2 | **12.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Geoffrey Domm](https://appshunter.io/developer/373378724) | [CuVee Software](https://appshunter.io/developer/424873503) |

## What reviewers say

### Janus Calculator

[App page](https://appshunter.io/ios/app/janus-calculator/id373378721)

This app offers a unique dual-calculator interface, supporting both standard and Reverse Polish Notation. It features programmable functions, extensive scientific and financial tools, and includes physical constants and an advanced option calculator.

**Highlights:** Dual calculator interface (Standard and RPN), Programmable functions, Finance and scientific functions, Physical constants, Black-Scholes option calculator, Implied value calculation

**Features:** macOS Compatibility

**In-app purchases:** none


### RPN

[App page](https://appshunter.io/ios/app/rpn-45-sd/id509923051)

This app is a detailed simulation of a 1973 scientific calculator, offering a photorealistic interface and all original functions. It includes powerful enhancements for modern use, such as complex number support and advanced date calculations.

**Highlights:** Photorealistic calculator simulation, Full HP-45 function implementation, Complex number support, Advanced date and time functions, Printer simulation for calculation records, Stopwatch functionality, Cut/copy/paste display values

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Janus Calculator free?

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

### Is RPN free?

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

### Which has better reviews, Janus Calculator or RPN?

RPN is rated higher. Janus Calculator averages 2.0 out of 5 from 1 ratings, while RPN averages 4.3 from 15 ratings.

### Do Janus Calculator or RPN have ads?

Neither Janus Calculator nor RPN shows ads.

### Which is updated more often, Janus Calculator or RPN?

Janus Calculator ships an update every 45 months, and RPN every 4 months. Most recently, Janus Calculator was updated on November 1, 2026 and RPN on November 1, 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.*