# Slide Rule vs RPN

The clearest difference is rating: RPN at 4.3 against Slide Rule's 1.0. RPN also leads on update cadence (every 4 months vs every 29 months) and ratings volume (15 vs 1). Slide Rule's advantage is price ($0.99 vs $1.99). On review sentiment, ads, in-app purchases and monetization model there is nothing between them.

Slide Rule costs $0.99 and RPN $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

RPN holds the better App Store score, 4.3 against 1.0. That said, the two scores are not equally well evidenced: RPN has 15 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 82% of RPN's.

Slide Rule ships an update every 29 months, RPN every 4 months. The most recent releases landed on October 27, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | Slide Rule | RPN |
| --- | --- | --- |
| Price | **$0.99** | $1.99 |
| Rating | [1.0 (1 ratings)](https://appshunter.io/ios/app/slide-rule/id288454455/reviews) | **[4.3 (15 ratings)](https://appshunter.io/ios/app/rpn-45-sd/id509923051/reviews)** |
| Number of ratings | 1 | **15** |
| Positive reviews | 75.0% of reviews | **81.8% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 29 months | **Every 4 months** |
| Monetization | Paid | Paid |
| Size | 3 MB | 14 MB |
| Requires iOS | 17.0 | **12.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Masayuki Akamatsu](https://appshunter.io/developer/284722836) | [CuVee Software](https://appshunter.io/developer/424873503) |

## 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


### RPN

[App page](https://appshunter.io/ios/app/rpn-45-sd/id509923051)

This app is a detailed simulation of a 1973 scientific calculator, offering a photorealistic interface and all original functions. It includes powerful enhancements for modern use, such as complex number support and advanced date calculations.

**Highlights:** Photorealistic calculator simulation, Full HP-45 function implementation, Complex number support, Advanced date and time functions, Printer simulation for calculation records, Stopwatch functionality, Cut/copy/paste display values

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Slide Rule free?

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

### Is RPN free?

RPN costs $1.99, with no in-app purchases.

### Which has better reviews, Slide Rule or RPN?

RPN is rated higher. Slide Rule averages 1.0 out of 5 from 1 ratings, while RPN averages 4.3 from 15 ratings.

### Do Slide Rule or RPN have ads?

Neither Slide Rule nor RPN shows ads.

### Which is updated more often, Slide Rule or RPN?

Slide Rule ships an update every 29 months, and RPN every 4 months. Most recently, Slide Rule was updated on October 27, 2026 and RPN on October 20, 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.*