# RPN 28x Calc vs DB40X

The clearest difference is price: DB40X at Free against RPN 28x Calc's $6.99. DB40X also leads on update cadence (every 3 weeks vs every 2 months). RPN 28x Calc's advantage is review sentiment (97% vs 78%) and rating (5.0 vs 4.7). On ads, in-app purchases and device support there is nothing between them.

DB40X is free to download; RPN 28x Calc costs $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

RPN 28x Calc holds the better App Store score, 5.0 against 4.7. Both are backed by a comparable volume of ratings — 34 and 7 respectively. Written reviews point the same way: 97% of RPN 28x Calc's written reviews are positive against 78% of DB40X's.

RPN 28x Calc ships an update every 2 months, DB40X every 3 weeks. The most recent releases landed on November 13, 2026 and November 4, 2026 respectively.

## The numbers

| Metric | RPN 28x Calc | DB40X |
| --- | --- | --- |
| Price | $6.99 | **Free** |
| Rating | **[5.0 (34 ratings)](https://appshunter.io/ios/app/rpn-28x-calc/id529927583/reviews)** | [4.7 (7 ratings)](https://appshunter.io/ios/app/db40x/id6624315901/reviews) |
| Number of ratings | **34** | 7 |
| Positive reviews | **97.1% of reviews** | 77.8% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 3 weeks** |
| Monetization | Paid | **Free** |
| Size | 3 MB | 7 MB |
| Requires iOS | **12.4** | 14.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [tredje design](https://appshunter.io/developer/495557933) | [Christophe de Dinechin](https://appshunter.io/developer/1761608161) |

## What reviewers say

### RPN 28x Calc

[App page](https://appshunter.io/ios/app/rpn-28x-calc/id529927583)

A programmable scientific calculator offering a classic aesthetic with modern functionality. It features a dynamic stack display, customizable buttons, and support for multiple data types, making complex calculations intuitive and accessible.

**Highlights:** Reverse Polish Notation (RPN) input, Dynamic stack display with scrolling, Customizable buttons and programming, Support for multiple data types (real, complex, binary, lists, etc.), 147 scientific units and physical constants, Interactive program debugging, Units and log viewers

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

**In-app purchases:** none


### DB40X

[App page](https://appshunter.io/ios/app/db40x/id6624315901)

A high-precision scientific calculator inspired by the HP48 series, offering arbitrary precision computations, complex numbers, vectors, matrices, and graphing. It supports RPN and algebraic operations, with over 1000 built-in functions and a hyperlinked help system.

**Highlights:** Arbitrary precision computations, RPN and algebraic operations, Complex numbers, vectors, and matrices, Graphing and plotting, Engineering units and conversions, Hyperlinked help system

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

**In-app purchases:** none


## Frequently asked questions

### Is RPN 28x Calc free?

RPN 28x Calc costs $6.99, with no in-app purchases.

### Is DB40X free?

DB40X is free to download, with no in-app purchases.

### Which has better reviews, RPN 28x Calc or DB40X?

RPN 28x Calc is rated higher. RPN 28x Calc averages 5.0 out of 5 from 34 ratings, while DB40X averages 4.7 from 7 ratings.

### Do RPN 28x Calc or DB40X have ads?

Neither RPN 28x Calc nor DB40X shows ads.

### Which is updated more often, RPN 28x Calc or DB40X?

RPN 28x Calc ships an update every 2 months, and DB40X every 3 weeks. Most recently, RPN 28x Calc was updated on November 13, 2026 and DB40X on November 4, 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.*