my41CX vs ThetaCalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
my41CX
Experience the most accurate HP-41CX calculator emulation. This app provides full microcode-level emulation of the original NUT processor, ensuring 100% hardware-accurate behavior. It features a modern interface, expandable ROM modules, and built-in documentation for a classic yet contemporary user experience.
- True microcode emulation
- Modern user interface
- Expandable with ROM modules
- Built-in documentation
- 100% hardware-accurate behavior
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The most accurate HP-41CX emulator available. my41cx delivers full microcode-level emulation of the legendary NUT processor, reproducing every behavior of the original hardware with complete fidelity. Built and refined over three major releases, my41cx v3 combines the precision of real hardware emulation with a modern interface designed for daily use. Key Features: - True Microcode Emulation: Not a simulation—an actual NUT processor emulator running original microcode for 100% hardware-accurate behavior. - Modern Interface, Classic Soul: A completely redesigned UI built for today's devices while preserving the authentic feel of the original calculator. - Expandable with ROM Modules: Load external ROM modules to extend the system, just like the real HP-41CX. - Built-in Documentation: Access manuals and reference material directly within the app—no need to search for PDFs. Perfect for engineers, students, scientists, and anyone who appreciates the elegance of HP's finest programmable calculator. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
ThetaCalc
This utility app provides a Reverse Polish Notation (RPN) calculator. Users can extend its functionality by programming custom functions and equations using JavaScript.
- Reverse Polish Notation (RPN) calculator
- User-programmable functions
- JavaScript equation support
- Extensible functionality
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ThetaCalc is a RPN (Reverse Polish Notation) calculator which can be extended by functions and equations programmed by the user in JavaScript.
Screenshots
Verdict
The clearest difference is review sentiment: ThetaCalc at 100% against my41CX's 43%. ThetaCalc also leads on in-app purchases (none vs 3) and ratings volume (4 vs 1). my41CX's advantage is rating (5.0 vs 4.3) and update cadence (every 2 months vs every 3 months). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. my41CX sells 3 in-app purchases, starting at $0.99 per month. ThetaCalc asks for nothing beyond the download.
my41CX holds the better App Store score, 5.0 against 4.3. Both are backed by a comparable volume of ratings — 1 and 4 respectively. Written reviews complicate that: 43% of my41CX's written reviews are positive against 100% of ThetaCalc's, so the app with the better star average is not the one people write more warmly about.
my41CX ships an update every 2 months, ThetaCalc every 3 months. The most recent releases landed on October 23, 2026 and October 1, 2026 respectively.
| Parameter | my41CX | ThetaCalc |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | 4.3 (4 ratings) |
| Positive reviews | 43.4% of reviews | 100.0% of reviews — better |
| Number of ratings | 1 | 4 — better |
| Update frequency | Every 2 months — better | Every 3 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad, Mac — better | iPhone, iPad |
| Requires iOS | 26.0 | 17.6 — better |
| Further details — not scored | ||
| Size | 5 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Miroslav Perovic | Felix Stehli |
Customer experience
my41CX
ThetaCalc
Bugs and requests
my41CX
Reported bugs
38 issues- Cannot enter anything via keyboard on Mac
- Locks up when running a program
- Crashes under IOS 13.2.3
- Application quits after touching screen
- Keys 'V' and 'W' inverted when ALPHA mode is switched on
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- GUI no longer accurate visual reproduction
- Incompatible with IOS 13.2
- Crashes systematically on hitting any key
- App closes after launch
- Not functional
- Unusable
- Crashes on startup
- App closes when touching keys
- Reverts to main screen when pressing buttons
- Flashes on screen and disappears
- Instant shutdown when trying to use it
- Shuts down as soon as screen is touched
- Shuts down when attempting to tap any key
- Crashes constantly after IOS update
- Closes the app as soon as you touch the screen
- Stopped working with iso 13.3
- Crashes as soon as I touch a key
- Broken on iOS 13.2
- Font for unshifted keys too small
- Functions faint and blurry
- Freezes when executing commands
- Low contrast
- No key feedback
- Unstable and crashes
- Slow performance
- Stopwatch function not real time
- Memory not reliably retained
- Loses all work
- Massive memory leaks
- Trashes program
- Incredibly slow
- Locks up
- Glitches while switching modes
Requested features
5 requests- Larger buttons
- Option for tactile/Haptic feedback for keys
- Option for beep sound
- Instructions for mod files
- Better Mac UI
ThetaCalc
Not enough reviews yet to summarise bugs or requests.
In-app purchases
my41CX
- Monthly$0.991 Month
- Yearly Premium$9.991 Year
- Unlock Full App$19.99
ThetaCalc
No in-app purchases
