my41CX vs Plus42
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/
Plus42
This advanced scientific calculator simulates the classic HP-42S RPN calculator with enhanced features. It offers algebraic expressions, unit conversions, directories for storage, a larger resizable display, financial functions, and 2D plotting with integral and root finding.
- HP-42S RPN calculator simulation
- Algebraic expressions
- Attached units and conversions
- Program and variable directories
- Resizable 8-row, 22-column display
- Time value of money and amortization
- 2D function plotting with zoom and pan
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Plus42 is an advanced scientific programmable calculator, based on Free42. Free42, in turn, is a complete re-implementation of the HP-42S scientific programmable RPN calculator, which was made from 1988 until 1995 by Hewlett-Packard. Free42 is a complete rewrite and contains no HP code whatsoever. Plus42 builds on Free42 and adds: Algebraic expressions modeled after those used on the HP-27S and HP-17B/19B; attached units and unit conversions modeled after those used on the HP-48/49/50 series; directories for more organized storage of programs and variables; a larger display, with 8 rows and 22 columns (131x64 pixels) by default, which the user may resize at will; time value of money and amortization schedules; and two-dimensional plotting of functions, with ability to zoom and pan, and find integrals and roots from points in the plot.
Screenshots
Verdict
my41CX and Plus42 both sit at 5.0 stars, but that hides the real split: 92% of Plus42's written reviews are positive against 43% of my41CX's. Plus42 also leads on in-app purchases (none vs 3) and update cadence (weekly vs every 2 months). my41CX's advantage is price (Free vs $9.99). On rating, 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
my41CX is free to download; Plus42 costs $9.99 up front. my41CX sells 3 in-app purchases, starting at $0.99 per month. Plus42 asks for nothing beyond the download.
On the App Store both sit at effectively the same score — 5.0 for my41CX against 4.9 for Plus42. That said, the two scores are not equally well evidenced: Plus42 has 79 ratings behind it against 1, so its average is the more settled of the two. Written reviews are what separate them: 43% of my41CX's written reviews are positive against 92% of Plus42's.
my41CX ships an update every 2 months, Plus42 weekly. The most recent releases landed on September 26, 2026 and September 22, 2026 respectively.
| Parameter | my41CX | Plus42 |
|---|---|---|
| Price | Free — better | $9.99 |
| Rating | 5.0 (1 ratings) — better | 4.9 (79 ratings) |
| Positive reviews | 43.4% of reviews | 92.3% of reviews — better |
| Number of ratings | 1 | 79 — better |
| Update frequency | Every 2 months | Weekly — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Best chart rank | — | #195 — better |
| Devices | iPhone, iPad, Mac | iPhone, iPad, iPod |
| Requires iOS | 26.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 5 MB | 11 MB |
| Age rating | 4+ | 4+ |
| Developer | Miroslav Perovic | Thomas Okken |
Customer experience
my41CX
Plus42
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
Plus42
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
Plus42
No in-app purchases








