# RPN vs HP

The clearest difference is price: HP at Free against RPN's $3.99. HP also leads on update cadence (every 11 days vs every 3 months) and ratings volume (58 vs 17). RPN's advantage is iOS requirement (12.0 vs 17.2). On rating, review sentiment, ads and in-app purchases there is nothing between them.

HP is free to download; RPN costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 4.6 for RPN against 4.6 for HP. Both are backed by a comparable volume of ratings — 17 and 58 respectively. Written reviews are what separate them: 93% of RPN's written reviews are positive against 100% of HP's.

RPN ships an update every 3 months, HP every 11 days. Both last shipped on October 24, 2026.

## The numbers

| Metric | RPN | HP |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[4.6 (17 ratings)](https://appshunter.io/ios/app/rpn-67-sd/id1109722386/reviews)** | [4.6 (58 ratings)](https://appshunter.io/ios/app/hp-35/id6738010641/reviews) |
| Number of ratings | 17 | **58** |
| Positive reviews | 92.9% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 11 days** |
| Monetization | Paid | **Free** |
| Size | 63 MB | 2 MB |
| Requires iOS | **12.0** | 17.2 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [CuVee Software](https://appshunter.io/developer/424873503) | [Enrique Haro](https://appshunter.io/developer/1778874870) |

## What reviewers say

### RPN

[App page](https://appshunter.io/ios/app/rpn-67-sd/id1109722386)

This app simulates a vintage programmable calculator from the mid-70s, offering enhanced features beyond the original. It allows users to run existing programs, manage virtual cards, and utilize advanced functions for scientific and engineering tasks.

**Highlights:** Virtual program and data cards, Virtual paper tape printer, Database-driven card manager, Create, label, and organize unlimited cards, Share cards via email, AirDrop, Dropbox, Editable program listings, Enhanced features for more program steps and registers

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

**In-app purchases:** none


### HP

[App page](https://appshunter.io/ios/app/hp-35/id6738010641)

Emulates classic Hewlett Packard RPN scientific calculators from the 1970s. Experience the original HP-35, HP-45, and HP-21 models on your iPhone.

**Highlights:** RPN calculator emulation, HP-35 model, HP-45 model, HP-21 model, Classic scientific calculator interface

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

**In-app purchases:** none


## Frequently asked questions

### Is RPN free?

RPN costs $3.99, with no in-app purchases.

### Is HP free?

HP is free to download, with no in-app purchases.

### Which has better reviews, RPN or HP?

RPN is rated higher. RPN averages 4.6 out of 5 from 17 ratings, while HP averages 4.6 from 58 ratings.

### Do RPN or HP have ads?

Neither RPN nor HP shows ads.

### Which is updated more often, RPN or HP?

RPN ships an update every 3 months, and HP every 11 days. Most recently, RPN was updated on October 24, 2026 and HP on October 24, 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.*