# Complex RPN Calculator — Complex Numbers RPN Calculator

> Scientific RPN calculator for complex numbers with polar and rectangular formats. (iPhone/iPad app by John Coddington.)

- Source: https://appshunter.io/ios/app/complex-rpn-calculator/id291826330 (this page in markdown: same URL + `.md`)
- Developer: [John Coddington](https://appshunter.io/developer/291826333)
- Category: Utilities
- Price: Free
- Rating: 3.82/5 from 22 App Store ratings · 87 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.4 · 1 MB
- Languages: English
- Released: 2008-09-27
- Data updated: 2026-08-23
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/complex-rpn-calculator/id291826330/reviews.md

## What is Complex RPN Calculator?

Complex RPN Calculator is a scientific RPN calculator with a four stack whose native number is complex. You can view and enter numbers in both polar and rectangular formats. Complex RPN remembers its state between usages and has 10 memory locations.

## Key features

- Complex number support
- Four-level stack
- Polar and rectangular formats
- State persistence
- 10 memory locations
- Scientific calculations

## What do users think of Complex RPN Calculator?

Overall sentiment: mixed

**Pros**

- ✅ Great RPN functionality
- ✨ Complex number support
- 🆓 Free to use
- 🚫 No ads or in-app purchases
- 💻 Works on macOS
- 👍 Simple and clean design
- 💡 Customizable key press sound
- 🗂️ Stack visibility

**Cons**

- 🎨 SwiftUI design is ugly
- 🐌 Slow keyboard response
- 🖱️ Clunky operation
- 📉 Complex number operations limited
- ⚠️ Broken on newer iOS versions (historically)
- 😵 Confusing for non-RPN users

**Commonly reported bugs**

- Mutes other apps when used
- Slow keyboard response after update
- X^3 calculation incorrect for large imaginary numbers
- App crashes on opening/button press (historical iOS 9 issues)
- App starts upside down in landscape on iPad (historical iOS 8 issue)
- Unreadable fonts on iPad (historical version 1.2 issue)

**Most requested features**

- Turn off key click sound
- Customize number display
- See the stack
- Fix slow entry response
- Fix imaginary number calculation (X^3)
- Improve SwiftUI design (less whitespace)
- Show all stack levels
- Add angle function
- Add magnitude function
- Add 'Clear X' button
- Make RAD/DEG toggle button
- Single button for Sci/Eng/Fix/Raw modes
- Add '//' (parallel) function
- Add 'Module' button
- Change 'i' to 'j' for imaginary part
- Show stack levels
- Add log2 function
- Add logGamma function
- Smaller buttons
- Add complex conjugate button
- Add real part button
- Add imaginary part button
- Add modulo function
- Make app start faster

## Recent user reviews (10 of 87)

All indexed reviews: https://appshunter.io/ios/app/complex-rpn-calculator/id291826330/reviews.md

### 5/5 — Great calculator with one odd interface issue

*2026-05-13, version 6.0*

I use this calculator for complex number calcs all the time but there’s one gotcha for a new user. It’s not obvious how to enter a number in polar format. To do so use the angle key to get it into polar display mode and then the ‘i’ key is used to enter the angle.

### 1/5 — Why does the app mute other apps?

*2023-07-30, version 5.0*

When playing music or listening to a podcast, when you use the  calculator it mutes the music.  Why?
This must be fixed. I’m looking for another rpn calculator that doesn’t do this?

Fix it please

### 5/5 — Good RPN

*2023-07-26, version 5.0*

This app is great! I have been using this app for years as a clean and simple, RPN scientific calculator. I was surprised to see the recent update to SwiftUI. On one hand, the update adds some great functionality, like the ability to turn the click sound from the key press off, maculate how the numbers are displayed, and let's you see the stack. On the other hand, SwiftUI is just downright fugly. There's no other way to say it. It really stinks. That isn't this developer's fault, it's Apple's. What makes it ugly is that there's too much border, or white space, around the buttons. IT's true for every other app I've seen migrated to SwiftUI. They all get ugly and harder to use.

### 1/5 — Update to SwiftUI has slow entries

*2023-07-12, version 5.0*

The calculator keyboard responds very slowly with this update. I can type 4-5 numbers before the first number appears. 

Very annoying and difficult to see if one has made a mistake on entry until a few seconds later. 

I am using an iPhone 14 Pro Max.

### 5/5 — Cool little Calculator

*2023-07-10, version 5.0*

Works well on MacOS

### 4/5 — Found a fault

*2022-03-20, version 3.0*

When an imaginary number like X=j1.837526E18 is entered X^2[X] is correct but X^3 is not.

### 5/5 — Best

*2021-09-11, version 3.0*

This app works a treat. Been using it for years. Don’t be put off by advice that it no longer functions.

### 3/5 — Gloss black and genuinely free!

*2021-06-04, version 3.0*

• RPN with complex numbers.
• A tiny app requiring next to no space.
• Very fast - but please see below!
• Completely devoid of silly banners and advertising.
• Highly polished appearance which suggests the developer enjoys symmetry!

Unfortunately, the need to scrutinise miniature graphics in an unusual layout leads to unintuitive, clunky operation.

### 5/5 — Complex number

*2019-10-05, version 3.0*

Easy and simple 
Complex number operations

### 5/5 — Free, simple, functional, no ads or in-app purchases. Awesome.

*2018-05-12, version 3.0*

So far so good on iPhone SE.

## Frequently asked questions about Complex RPN Calculator

### What is Complex RPN Calculator?

Complex RPN Calculator is a scientific calculator designed for complex number operations. It uses a four-level stack and allows input and display of numbers in both polar and rectangular formats.

### What are the key features of this calculator?

Key features include native support for complex numbers, a four-level stack, the ability to view and enter numbers in polar and rectangular formats, state persistence between uses, and 10 memory locations for storing values.

### Is this app free to use?

Yes, the application is available for free. There are no in-app purchases or advertisements mentioned, indicating a completely free user experience.

### Who would benefit from using Complex RPN Calculator?

This app is ideal for individuals involved in fields like engineering, science, and advanced mathematics who frequently work with complex numbers and prefer the efficiency of Reverse Polish Notation.

## Version history (last 5 releases)

### 6.0 — 2025-09-18

Fixed some bugs associated with setting the significant digits in FIX, SCI and ENG modes that were causing crashes

Changed the way Pi modifies the stack to make it more intuitive.

Added a mode to show the stack when in landscape mode. Be away that when you are entering a number, x will show as 0.

If you are experiencing button lag or don't like not being able to play music in the background, change Click Style to none and this will fix your problems.

### 5.0 — 2023-07-10

Updated to SwiftUI

### 3.0 — 2016-01-09

This app has been updated by Apple to display the Apple Watch app icon.

Updating with fancy new buttons.

### 2.3.1 — 2012-05-25

Updating links to point to new web page location.

### 2.3 — 2012-04-17

Updating graphics for new iPad.

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## More apps by John Coddington

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All apps by John Coddington: https://appshunter.io/developer/291826333

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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 2026-08-23.*