# Halcyon Calc

> Advanced scientific calculator for numerical and symbolic computation. (iPhone/iPad app by Halcyon Touch Software.)

- Source: https://appshunter.io/ios/app/halcyon-calc/id327064659 (this page in markdown: same URL + `.md`)
- Developer: [Halcyon Touch Software](https://appshunter.io/developer/327064662)
- Category: Utilities, Education
- Price: $4.99
- Rating: 4.90/5 from 18 App Store ratings · 6 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.6 · 10 MB
- Languages: American English
- Released: 2009-08-22
- Data updated: 2026-08-29
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/halcyon-calc/id327064659/reviews.md

## What is Halcyon Calc?

For students, engineers, scientists or people who fondly remember classic calculators, Halcyon Calc is a great application for manipulating numbers and even symbolic expressions.

Features:
- Use this calculator on an iPhone, iPod Touch or an iPad
- Use your finger to quickly scroll through the stack to review intermediate results
- Copy and paste support
- Over 225 built-in operations, including trig, logarithms, real functions, complex operations and more
- Allows you to work with real, complex and integer numbers.
- Real and complex numbers can be displayed in standard, fixed, scientific and engineering format
- Use over 120 built-in units to perform unit conversion or create your own units if the one you want is not already there
- Integer numbers can be displayed in decimal, hexadecimal, octal and binary bases
- Work with real and complex matrices and vectors.
- Enter symbolic expressions and solve them for different values. Even better, solve quadratic formulas, collect and expand factors and terms, find minima, maxima and roots of any expression.
- Plot symbolic expressions in X/Y coordinates.  Pan the coordinate space by dragging the plot in any direction.  Zoom in and out using a pinch gesture.
- Determine symbolic derivative, taylor series or numeric integral of an expression.
- Store numbers, lists, strings and expressions in symbols.  Create hierarchies of symbols to allow you to organize your calculations.
- Create sequences of calculator commands into programs, creating your own operations which you can then include in expressions.
- Store statistical data and calculate totals, averages, standard deviations, linear regressions, etc over that data.
- Calculate the probabilities associated with standard distributions like the normal, F and T distributions.

## Key features

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

## Recent user reviews (6 of 6)

All indexed reviews: https://appshunter.io/ios/app/halcyon-calc/id327064659/reviews.md

### 5/5 — Great simulator of a great calculator and a great app

*2022-05-22*

This is truly one of the best. Faithful reproduction of the HP-28S, the first user RPL calculator, that keeps all the good stuff and improves on the not-so-good (the display, for example, is so much better than that on the actual calculator). Stable and well thought out, with a very polished look. The plotting capabilities are pretty amazing. Very responsive developer; helped me immediately with a workaround to a minor problem and released an update within a few days. Allows me to do anything I used to do with my old 28S, and without the creaking plastic clamshell case sound! Highly recommended and worth every penny of the price. Hope to see more from this developer.

### 5/5 — Works well with M1 Macs

*2021-11-12, version 4.2.3*

Using this now in Monterey and it works like a charme. Even the Mac's keyboard is fully supported.

### 5/5 — Best Calculator out there

*2020-08-18*

Love how responsive Halcyon Software is to fixing and improving this software. My favorite change on this release is the long or 3D press to get the red shift key. 

My 28S still runs perfectly but the battery door is so fragile. I can use Halcyon Calc all the time.

### 5/5 — Marvellous

*2020-03-04, version 4.1*

I have bought about 6 calculators for ios, looking for a good HP RPN equivalent.
This is the best -  its not just an emulator, but has been written from scratch to keep the great original features but improve them too, e.g. graph plotting at native resolution.

### 5/5 — It works better than I had hoped!

*2019-05-12*

My HP 28S calculator (the best programmable scientific calculator ever built) is back!  Thanks so much!  I took a rather complicated engineering program from my 28 (which used some rather esoteric functions),  laid it in, and it ran perfectly!  Two thumbs WAY up!  More if I had them.

**Developer response:** Thanks so much for the review and so glad to hear that your programs from back in the day just worked in the app. I strive to reproduce the behaviour of the 28S but sometimes fall short. If you do find something in the future which seems wrong, let me know and I will try to fix it for you. 

Thanks again for the feedback.

### 4/5 — My favorite RPN calculator

*2013-03-26*

I went to college in the late 80's with an HP-28S. I still have the HP calculator, and it still works; and I'd been wanting an RPN calc for the phone that was similar to that one. There are a bunch of HP-12-like apps, but this is the first one I've found that behaves similar to the 28S. Very happy with Halcyon Calc; I've been able to delete all the other RPN calculator apps that I've tried.

## Frequently asked questions about Halcyon Calc

### What devices does Halcyon Calc support?

Halcyon Calc is available for iPhone, iPod Touch, and iPad. It offers a seamless experience across these Apple devices.

### How much does Halcyon Calc cost?

Halcyon Calc is a paid application priced at $4.99. This one-time purchase grants you access to all its advanced features.

### Does Halcyon Calc have ads?

No, Halcyon Calc is completely ad-free. You can perform calculations without any interruptions from advertisements.

### What kind of mathematical operations can Halcyon Calc perform?

Halcyon Calc supports over 225 built-in operations, including trigonometric functions, logarithms, real and complex number operations, matrix and vector calculations, and symbolic differentiation and integration.

### Can Halcyon Calc handle unit conversions?

Yes, Halcyon Calc includes over 120 built-in units for conversion and allows you to create your own custom units if needed.

### What is the age rating for Halcyon Calc?

Halcyon Calc has an age rating of 4+, making it suitable for a wide range of users.

### How often is Halcyon Calc updated?

The latest version, 4.2.10, was released on October 8, 2025, indicating regular updates to enhance functionality and reliability.

### Can I plot functions with Halcyon Calc?

Yes, Halcyon Calc allows you to plot symbolic expressions in X/Y coordinates. You can pan and zoom the plot using intuitive gestures.

## Version history (last 5 releases)

### 4.3 — 2026-05-06

In this version, the size of the font in the display area will grow or shrink based on the user's "Text Size" setting in the "Display & Brightness" section of the system settings.  So, if you have your text size increased from default, you should find that the text in the display of the calculator will also be somewhat larger and easier to read.  If you have the setting low so that your text tends to be smaller than default, you should find that the text in the display of the calculator will also be smaller and show more content on your screen.

Let us know if the behaviour is not to your liking and we can tweak this behaviour in future versions.

### 4.2.10 — 2025-10-08

Minor UI fixes:
- On the iPad, the bottom of the stack was not always visible.  This should now be fixed.
- On the iPhone, there was sometimes a background colour leaking through along the top of the UI which should not have been visible.

### 4.2.9 — 2023-05-04

Fix COMB and PERM to correctly return one when doing combinations or permutations in groups of zero.

### 4.2.8 — 2023-03-17

Fixes the order of arguments restored by the LAST command with a series of multi-argument operations.  Prior to this, some operations would restore their arguments in reverse order.  Now, they should all restore their arguments correctly.

### 4.2.7 — 2022-11-21

Fix a bug where the display panel may not be visible on relaunch on an iPad.

## Apps similar to Halcyon Calc

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [CalCollections](https://appshunter.io/ios/app/calcollections/id6746972417) | — | Free | Utilities |
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## More apps by Halcyon Touch Software

- [Halcyon Calc Lite](https://appshunter.io/ios/app/halcyon-calc-lite/id408004888)
- [ListenerGS](https://appshunter.io/ios/app/listenergs/id1613273510)

All apps by Halcyon Touch Software: https://appshunter.io/developer/327064662

## Related topics

[halcyon touch software](https://appshunter.io/ios/topics/halcyon-touch-software) · [halcyon calc lite](https://appshunter.io/ios/topics/halcyon-calc-lite)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-29.*