i41CX vs RPN
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
i41CX
This app offers a powerful RPN scientific calculator experience, functionally equivalent to the HP-41CX. It includes over 300 built-in functions, programmability, and device integrations. Advanced features can be unlocked via in-app purchases.
- RPN logic with 4-element stack
- Over 300 built-in functions
- Programmable up to 2000 lines
- User-definable keyboard
- Bluetooth keyboard support
- Device integration features
- Calculator skins and mini stack display
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i41CX is the same powerful advanced programmable RPN scientific calculator as the highly acclaimed i41CX+ but without the latter’s incredibly advanced capabilities such as the printer, expansion, CAS, etc. It is functionally equivalent to the world-renowned HP-41CX and inherits all of the i41CX+ usability features including extremely responsive and animated key clicks, audible key feedback sounds, optimally spaced keys for accurate input, traditional and upbeat modern diverse set of skins, etc. If you are looking for a powerful programmable RPN scientific calculator but don’t need all of the capabilities of i41CX+ then i41CX is for you. And best of all, if you ever decide that you need the more advanced capabilities of i41CX+ you can enable them using secure in-app purchases right within the app! FEATURES: • RPN logic with a 4 element deep memory stack • 319 main and 124 extended memory registers • Over 300 built-in functions, including nearly 100 functions created specifically for i41CX • Time, calendar, alarm, and stopwatch functions • Rich set of functions and algorithms: numerical, mathematical, statistical, and much more • Access to the entire HP-41 library of solutions for science, mathematics, statistics, engineering, business, financial, surveying, medicine, real estate, and many other domains • Programmable - Over 2000 lines • User definable keyboard • Ability to operate the calculator using a Bluetooth keyboard • Device integration: external display mirroring, copy and paste, GPS, accelerometer, digital compass, time and date synchronization, and much more • iOS 8 Notification Center widget • Sound support including synthetic tones and interface sounds • Support for calculator skins and optional mini stack display • Adjustable sound volume and display colors • Usage & Examples table with usage tips and examples • Quick reference guide of all built-in functions • Beautiful and clean user interface *********************************************************** A comprehensive FAQ is available at http://alsoftiphone.com/i41CX. Please don't hesitate to use the "Contact Us" link there if you cannot find the answers or information that you seek. Thank you.
RPN
This app simulates a legendary scientific calculator, offering photo-realistic visuals and advanced functions like integration and root finding. It includes built-in programs and extensions for enhanced usability, making it a powerful tool for complex calculations.
- Photo-realistic look-and-feel
- Programmable with 999 steps
- Integration and root solving
- Built-in application programs
- Live register view
- Program library and backup
- Sharing via email, AirDrop, Dropbox
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RPN-34 CE is the first photo-realistic simulation of Hewlett-Packard's popular mid-range scientific calculator HP-34C for the iPhone. Produced from 1979 through 1983, it was the "Basil" member of the third-generation HP calculators known as the "Spice" series. It was the first pocket-calculator ever capable of doing integration and root finding. While the simulator works like the original calculator, a number of carefully designed extensions, along with the tremendously improved speed, make it joy to use even today. RPN-34 CE comes with the programs of HP's "Applications", "Mathematics", "Surveying", "Student Engineering", and "Statistics" application books built-in! Handbooks may be downloaded from CuVee Software's website. Features: • Photo-realistic look-and-feel • Programmable (999 steps), subroutines, 12 labels, 10 flags • 100 registers, "continuous", with full store/recall arithmetic • "Live" register view • Program listing view with intelligent navigation • Program library, easily backed-up via iTunes • Store and retrieve any number of programs • Sharing: e-mail, AirDrop, Dropbox, copy, paste, print • 62 programs pre-installed (53 original HP) Calculator functions: • Integration, root solving • Statistics (mean, standard deviation, linear regression, normal distribution) • Factorial of any number (normal and logarithmic) • Trigonometric and hyperbolic functions (degrees, radians, grads) • Polar/rectangular conversions • Inverse, square root, logarithm, exponential, pi • Storage arithmetic (both store and recall) • Statistics (average, standard deviation, y-estimate, linear regression) • Unit and hours conversions • 31 additional functions not found on the HP-34C, like time and sound Details: cuveesoft.ch/rpn34
Screenshots
Verdict
The clearest difference is in-app purchases: RPN at none against i41CX's 4. RPN also leads on price ($1.99 vs $7.99) and rating (5.0 vs 4.7). i41CX's advantage is update cadence (every 3 days vs every 3 months) and ratings volume (47 vs 14). On 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
i41CX costs $7.99 and RPN $1.99 up front. i41CX sells 4 one-off in-app purchases. RPN asks for nothing beyond the download.
RPN holds the better App Store score, 5.0 against 4.7. Both are backed by a comparable volume of ratings — 47 and 14 respectively. Written reviews point the same way: 90% of i41CX's written reviews are positive against 100% of RPN's.
i41CX ships an update every 3 days, RPN every 3 months. Both last shipped on November 10, 2026.
| Parameter | i41CX | RPN |
|---|---|---|
| Price | $7.99 | $1.99 — better |
| Rating | 4.7 (47 ratings) | 5.0 (14 ratings) — better |
| Positive reviews | 90.5% of reviews | 100.0% of reviews — better |
| Number of ratings | 47 — better | 14 |
| Update frequency | Every 3 days — better | Every 3 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Devices | iPhone, iPad | iPhone, iPod |
| Requires iOS | 16.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 135 MB | 16 MB |
| Age rating | 4+ | 4+ |
| Developer | Antonio Lagana | CuVee Software |
Customer experience
i41CX
RPN
In-app purchases
i41CX
- Overlays Upgrade$2.99
- Printer Upgrade$3.99
- CAS Upgrade$7.99
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- i41CX+ Features Upgrade$17.99
RPN
No in-app purchases









