# RPNPro

> RPN calculator with four-level stack for software engineers. (iPhone/iPad app by Felix Meier.)

- Source: https://appshunter.io/ios/app/rpnpro/id603155368 (this page in markdown: same URL + `.md`)
- Developer: [Felix Meier](https://appshunter.io/developer/603155771)
- Category: Utilities, Productivity
- Price: Free
- Rating: 5.00/5 from 1 App Store ratings · 2 written reviews indexed
- Age rating: 4+
- Requires: iOS 9.1 · 1 MB
- Languages: American English
- Released: 2013-02-28
- Data updated: 2026-06-05
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/rpnpro/id603155368/reviews.md

## What is RPNPro?

RPNPro is a calculator for software engineers.

RPNPro uses RPN (Reverse Polish Notation) as an input scheme. It is based on the same four level stack model as provided by the original HP (Hewlett-Packard) calculators, featuring X, Y, Z and T registers.

The contents of the X register are always shown in decimal, hexadecimal and binary notation.

## Key features

- Reverse Polish Notation (RPN) input
- Four-level stack (X, Y, Z, T registers)
- Decimal, hexadecimal, and binary display
- Modeled after HP calculators
- Designed for software engineers

## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/rpnpro/id603155368/reviews.md

### 3/5 — Nice calculator

*2021-02-11*

It’d be better to have a full screen display on iPad. Thanks in advance. Cheers!

### 5/5 — Nice job

*2013-04-27*

Love this, make my job easier

## Frequently asked questions about RPNPro

### What is RPNPro?

RPNPro is a free calculator application that uses Reverse Polish Notation (RPN) for input, similar to classic Hewlett-Packard calculators. It features a four-level stack and displays the X register in decimal, hexadecimal, and binary.

### Is RPNPro free to use?

Yes, RPNPro is completely free to download and use. It does not have any in-app purchases or advertisements.

### What devices does RPNPro support?

RPNPro is available for iPhone, iPad, and iPod touch devices, running on iOS.

### How often is RPNPro updated?

The latest version of RPNPro was released on March 12, 2019. It was originally released on February 28, 2013.

### What is the age rating for RPNPro?

RPNPro has an age rating of 4+, making it suitable for a wide range of users.

### Does RPNPro have ads?

No, RPNPro is ad-free. Users can enjoy a clean and uninterrupted calculation experience.

### What makes RPNPro suitable for software engineers?

RPNPro's RPN input scheme and its ability to display numbers in decimal, hexadecimal, and binary are particularly useful for software engineers who frequently work with different number bases.

### What is the user sentiment for RPNPro?

Based on the available data, RPNPro has received a perfect rating of 5.0 stars from one review, indicating very positive user sentiment.

## Version history (last 3 releases)

### 1.2 — 2019-03-12

auto-adapts to all display sizes

### 1.1 — 2017-02-02

Upgrade for 64 bit devices.

### 1.0 — 2013-02-20

No release notes.

## Apps similar to RPNPro

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Halcyon Calc Lite](https://appshunter.io/ios/app/halcyon-calc-lite/id408004888) | 4.7 (15) | Free | Utilities |
| [RePNCalc - RPN Calculator Pro](https://appshunter.io/ios/app/repncalc-rpn-calculator-pro/id969780852) | 5.0 (1) | Free | Utilities |
| [Calccis](https://appshunter.io/ios/app/calccis/id6446233205) | — | Free | Utilities |
| [bcRPN](https://appshunter.io/ios/app/bcrpn/id1614744829) | 4.8 (4) | Free | Utilities |
| [ThetaCalc](https://appshunter.io/ios/app/thetacalc/id1521614636) | 4.3 (4) | Free | Utilities |
| [RPN-67 SD](https://appshunter.io/ios/app/rpn-67-sd/id1109722386) | 4.6 (16) | $3.99 | Utilities |

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-05.*