# Haihaisoft Reader vs RPN

The clearest difference is review sentiment: RPN at 93% against Haihaisoft Reader's 0%. RPN also leads on rating (4.6 vs 1.2) and ratings volume (17 vs 5). Haihaisoft Reader's advantage is price (Free vs $3.99) and iOS requirement (6.1 vs 12.0). On update cadence, ads, in-app purchases and device support there is nothing between them.

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

RPN holds the better App Store score, 4.6 against 1.2. Both are backed by a comparable volume of ratings — 5 and 17 respectively. Written reviews point the same way: 0% of Haihaisoft Reader's written reviews are positive against 93% of RPN's.

Haihaisoft Reader ships an update every 5 months, RPN every 3 months. The most recent releases landed on October 8, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | Haihaisoft Reader | RPN |
| --- | --- | --- |
| Price | **Free** | $3.99 |
| Rating | [1.2 (5 ratings)](https://appshunter.io/ios/app/haihaisoft-reader/id437433430/reviews) | **[4.6 (17 ratings)](https://appshunter.io/ios/app/rpn-67-sd/id1109722386/reviews)** |
| Number of ratings | 5 | **17** |
| Positive reviews | 0.0% of reviews | **92.9% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Every 3 months** |
| Monetization | **Free** | Paid |
| Size | 21 MB | 63 MB |
| Requires iOS | **6.1** | 12.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [海波 师](https://appshunter.io/developer/437433433) | [CuVee Software](https://appshunter.io/developer/424873503) |

## What reviewers say

### Haihaisoft Reader

[App page](https://appshunter.io/ios/app/haihaisoft-reader/id437433430)

A free PDF reader for iOS devices that offers fast launch speeds. It can also open PDF documents protected by DRM-X 3.0. Requires iOS 6 or later.

**Highlights:** Free PDF document reader, Fast launch speed, DRM-X 3.0 protected PDF support, iOS compatibility

**Features:** macOS Compatibility

**In-app purchases:** none


### 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


## Frequently asked questions

### Is Haihaisoft Reader free?

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

### Is RPN free?

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

### Which has better reviews, Haihaisoft Reader or RPN?

RPN is rated higher. Haihaisoft Reader averages 1.2 out of 5 from 5 ratings, while RPN averages 4.6 from 17 ratings.

### Do Haihaisoft Reader or RPN have ads?

Neither Haihaisoft Reader nor RPN shows ads.

### Which is updated more often, Haihaisoft Reader or RPN?

Haihaisoft Reader ships an update every 5 months, and RPN every 3 months. Most recently, Haihaisoft Reader was updated on October 8, 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.*