# RPN vs Petal Layout Pro

The clearest difference is review sentiment: RPN at 71% against Petal Layout Pro's 0%. RPN also leads on update cadence (every 6 months vs every 41 months) and price ($1.99 vs $3.99). On ads, in-app purchases, monetization model and device support there is nothing between them.

RPN costs $1.99 and Petal Layout Pro $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

RPN ships an update every 6 months, Petal Layout Pro every 41 months. The most recent releases landed on November 1, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | RPN | Petal Layout Pro |
| --- | --- | --- |
| Price | **$1.99** | $3.99 |
| Rating | **[4.4 (14 ratings)](https://appshunter.io/ios/app/rpn-35-sd/id956224485/reviews)** | — |
| Number of ratings | **14** | — |
| Positive reviews | **71.4% of reviews** | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 6 months** | Every 41 months |
| Monetization | Paid | Paid |
| Size | 14 MB | 1 MB |
| Requires iOS | **12.0** | 16.1 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [CuVee Software](https://appshunter.io/developer/424873503) | [Imran Pinjara](https://appshunter.io/developer/1484488781) |

## What reviewers say

### RPN

[App page](https://appshunter.io/ios/app/rpn-35-sd/id956224485)

This app emulates the first pocket scientific calculator, offering a photo-realistic vintage experience. It simulates original operating speeds and unique arithmetic bugs, with optional modern enhancements like non-volatile registers.

**Highlights:** Photo-realistic look-and-feel, Multiple vintage skins, Vintage and Enhanced modes, Optional key-click and key-glow, Swipe to correct input, Display stack and memory registers

**Features:** macOS Compatibility

**In-app purchases:** none


### Petal Layout Pro

[App page](https://appshunter.io/ios/app/petal-layout-pro/id1486823832)

This app assists in the fabrication of spherical and hemispherical heads by calculating precise petal layouts. It supports various part divisions for accurate flat pattern development, ideal for pressure vessel and storage tank construction.

**Highlights:** Sphere petal layout calculation, Hemispherical head petal layout calculation, Multiple part divisions (12, 24, 48), Unit setting for mm/inches, Flat pattern development, Supports pressure vessel fabrication

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

**In-app purchases:** none


## Frequently asked questions

### Is RPN free?

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

### Is Petal Layout Pro free?

Petal Layout Pro costs $3.99, with no in-app purchases.

### Do RPN or Petal Layout Pro have ads?

Neither RPN nor Petal Layout Pro shows ads.

### Which is updated more often, RPN or Petal Layout Pro?

RPN ships an update every 6 months, and Petal Layout Pro every 41 months. Most recently, RPN was updated on November 1, 2026 and Petal Layout Pro on October 29, 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.*