# RPN Calc vs Halcyon Calc

The clearest difference is review sentiment: Halcyon Calc at 100% against RPN Calc's 34%. Halcyon Calc also leads on rating (4.9 vs 4.0) and ratings volume (18 vs 6). RPN Calc's advantage is price ($0.99 vs $4.99). On update cadence, ads, in-app purchases and device support there is nothing between them.

RPN Calc costs $0.99 and Halcyon Calc $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Halcyon Calc holds the better App Store score, 4.9 against 4.0. Both are backed by a comparable volume of ratings — 6 and 18 respectively. Written reviews point the same way: 34% of RPN Calc's written reviews are positive against 100% of Halcyon Calc's.

RPN Calc ships an update every 3 months, Halcyon Calc every 4 months. The most recent releases landed on November 8, 2026 and November 6, 2026 respectively.

## The numbers

| Metric | RPN Calc | Halcyon Calc |
| --- | --- | --- |
| Price | **$0.99** | $4.99 |
| Rating | [4.0 (6 ratings)](https://appshunter.io/ios/app/rpn-calc/id285002799/reviews) | **[4.9 (18 ratings)](https://appshunter.io/ios/app/halcyon-calc/id327064659/reviews)** |
| Number of ratings | 6 | **18** |
| Positive reviews | 34.3% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 4 months |
| Monetization | **Free** | Paid |
| Size | 3 MB | 10 MB |
| Requires iOS | **16.0** | 16.6 |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [James Mattis](https://appshunter.io/developer/285002802) | [Halcyon Touch Software](https://appshunter.io/developer/327064662) |

## What reviewers say

### RPN Calc

[App page](https://appshunter.io/ios/app/rpn-calc/id285002799)

This app provides a straightforward reverse Polish notation (RPN) calculator experience, inspired by classic HP models. It offers a clean interface with large buttons for quick calculations on iPhone, iPad, and Apple Watch, along with a convenient Today Extension for immediate access.

**Highlights:** Reverse Polish Notation (RPN) input, Clean, simple interface, Large, easy-to-press buttons, iPhone, iPad, and Apple Watch support, Today Extension for quick access

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support, iPhone Duo support

**In-app purchases:** none


### Halcyon Calc

[App page](https://appshunter.io/ios/app/halcyon-calc/id327064659)

A powerful calculator app for students, engineers, and scientists. It handles complex numbers, symbolic expressions, unit conversions, and matrix operations, with advanced plotting and programming capabilities.

**Highlights:** Complex number calculations, Symbolic expression manipulation, Unit conversion with custom units, Matrix and vector operations, Symbolic plotting, Programming of custom operations, Statistical data analysis

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

**In-app purchases:** none


## Frequently asked questions

### Is RPN Calc free?

RPN Calc costs $0.99, with no in-app purchases.

### Is Halcyon Calc free?

Halcyon Calc costs $4.99, with no in-app purchases.

### Which has better reviews, RPN Calc or Halcyon Calc?

Halcyon Calc is rated higher. RPN Calc averages 4.0 out of 5 from 6 ratings, while Halcyon Calc averages 4.9 from 18 ratings.

### Do RPN Calc or Halcyon Calc have ads?

Neither RPN Calc nor Halcyon Calc shows ads.

### Which is updated more often, RPN Calc or Halcyon Calc?

RPN Calc ships an update every 3 months, and Halcyon Calc every 4 months. Most recently, RPN Calc was updated on November 8, 2026 and Halcyon Calc on November 6, 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.*