# RPN vs CheckOne

The clearest difference is price: CheckOne at Free against RPN's $1.99. RPN's advantage is in-app purchases (none vs 1) and iOS requirement (12.0 vs 17.0). On ads and device support there is nothing between them.

CheckOne is free to download; RPN costs $1.99 up front. CheckOne sells 1 one-off in-app purchase. RPN asks for nothing beyond the download.

## The numbers

| Metric | RPN | CheckOne |
| --- | --- | --- |
| Price | $1.99 | **Free** |
| Rating | **[5.0 (14 ratings)](https://appshunter.io/ios/app/rpn-34-ce/id1448593029/reviews)** | — |
| Number of ratings | **14** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | — |
| Monetization | Paid | — |
| Size | 16 MB | 14 MB |
| Requires iOS | **12.0** | 17.0 |
| Devices | iPhone, iPod | iPhone, Apple Watch |
| Age rating | 4+ | 4+ |
| Developer | [CuVee Software](https://appshunter.io/developer/424873503) | [Mishima Design](https://appshunter.io/developer/373060551) |

## What reviewers say

### RPN

[App page](https://appshunter.io/ios/app/rpn-34-ce/id1448593029)

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.

**Highlights:** 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

**Features:** macOS Compatibility

**In-app purchases:** none


### CheckOne

[App page](https://appshunter.io/ios/app/checkone/id6785709065)

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| CheckOne Plus | $9.99 | one-time |


## Frequently asked questions

### Is RPN free?

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

### Is CheckOne free?

CheckOne is free to download, with in-app purchases available.

### Do RPN or CheckOne have ads?

Neither RPN nor CheckOne shows ads.

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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.*