# Slide Rule vs i41CX+

The clearest difference is price: Slide Rule at $0.99 against i41CX+'s $24.99. i41CX+'s advantage is rating (4.8 vs 1.0) and update cadence (every 5 weeks vs every 29 months). On ads, in-app purchases, monetization model and device support there is nothing between them.

Slide Rule costs $0.99 and i41CX+ $24.99 up front. Neither carries in-app purchases, so what you see is what you pay.

i41CX+ holds the better App Store score, 4.8 against 1.0. That said, the two scores are not equally well evidenced: i41CX+ has 106 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 75% of Slide Rule's written reviews are positive against 91% of i41CX+'s.

Slide Rule ships an update every 29 months, i41CX+ every 5 weeks. The most recent releases landed on September 21, 2026 and September 25, 2026 respectively.

## The numbers

| Metric | Slide Rule | i41CX+ |
| --- | --- | --- |
| Price | **$0.99** | $24.99 |
| Rating | [1.0 (1 ratings)](https://appshunter.io/ios/app/slide-rule/id288454455/reviews) | **[4.8 (106 ratings)](https://appshunter.io/ios/app/i41cx-plus/id289068865/reviews)** |
| Number of ratings | 1 | **106** |
| Positive reviews | 75.0% of reviews | **91.3% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 29 months | **Every 5 weeks** |
| Monetization | Paid | Paid |
| Size | 3 MB | 123 MB |
| Requires iOS | 17.0 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Masayuki Akamatsu](https://appshunter.io/developer/284722836) | [Antonio Lagana](https://appshunter.io/developer/289068868) |

## What reviewers say

### Slide Rule

[App page](https://appshunter.io/ios/app/slide-rule/id288454455)

Simulates a mechanical analog computer for scientific and engineering calculations. Perform multiplication, division, roots, and trigonometric functions with a digital slide rule.

**Highlights:** Multiplication and division, Square and cube roots, Trigonometry functions, Logarithm calculations, Digital slide rule simulation, Mechanical analog computer

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

**In-app purchases:** none


### i41CX+

[App page](https://appshunter.io/ios/app/i41cx-plus/id289068865)

This advanced RPN scientific calculator offers workstation-class Computer Algebra System (CAS) capabilities, going beyond traditional replicas. It provides access to an extensive library of modules and programs, enhanced with iOS features, customizable skins, and iCloud support for seamless data management.

**Highlights:** RPN logic with 4-element stack, Extensive memory registers, Over 400 built-in functions, Computer Algebra System (CAS), Virtual thermal printer/plotter, Access to HP-41 module library, Customizable skins and keyboard overlays

**In-app purchases:** none

**What reviewers like**

- 🚀 Fantastic emulation of the original HP41 calculator
- 🔒 Faithful to the original hardware and functionality
- 👍 Includes all the expansion modules and accessories
- 👍 Responsive and never crashes
- 👍 Excellent implementation of RPN and programmability

**What reviewers complain about**

- 🔋 Can drain battery when left on
- 👎 Small button size can lead to mis-taps
- 👎 Slow startup time in some versions

**Reported bugs**

- Issues with the 41Z math module producing garbled output
- Scaling problems with overlays

**Requested features**

- Landscape mode for better button size
- Haptic feedback for button presses
- Ability to load and save programs/modules via cloud/email
- Macros or scripting support


## Frequently asked questions

### Is Slide Rule free?

Slide Rule costs $0.99, with no in-app purchases.

### Is i41CX+ free?

i41CX+ costs $24.99, with no in-app purchases.

### Which has better reviews, Slide Rule or i41CX+?

i41CX+ is rated higher. Slide Rule averages 1.0 out of 5 from 1 ratings, while i41CX+ averages 4.8 from 106 ratings.

### Do Slide Rule or i41CX+ have ads?

Neither Slide Rule nor i41CX+ shows ads.

### Which is updated more often, Slide Rule or i41CX+?

Slide Rule ships an update every 29 months, and i41CX+ every 5 weeks. Most recently, Slide Rule was updated on September 21, 2026 and i41CX+ on September 25, 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.*