# Complex RPN Calculator — user reviews > 87 indexed App Store user reviews of Complex RPN Calculator by John Coddington, rated 3.82/5 from 22 ratings. - Source: https://appshunter.io/ios/app/complex-rpn-calculator/id291826330/reviews - App overview in markdown: https://appshunter.io/ios/app/complex-rpn-calculator/id291826330.md - Rating breakdown: 5★ 13 · 4★ 3 · 3★ 0 · 2★ 1 · 1★ 5 ## 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 ## Newest reviews (10 of 87) ### 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. ### 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. ### 4/5 — Good RPN Calculator *2018-01-04, version 3.0* The design is clean and it’s RPN. It would be nice if it showed the stack but that’s my only quibble. ### 3/5 — Fonts on iPad *2016-03-19, version 3.0* I recently installed the latest version (1.2 ?) and on the iPad 2, the labels on the buttons are now using an underlined small Helvetica font. As a result, many of them are unreadable. The previous version used a much better font. It would be nice if the app allowed enlarging the fonts for old people like me with vision issues. Would give this app 5 stars if the fonts were fixed. ### 3/5 — Get the PRO version *2015-12-16, version 2.3.1* Coddington has a PRO version of his RPN calculator app that works fine on iOS 9. It does not show both of the functions at the same time for keys that do double duty like the regular version did (for example X squared and square root of X), but at least it doesn't crash and doesn't have the annoying upside down "feature". For the second function keys, just type the 2nd key in the bottom left corner, and the entire keyboard now shows them. Hope the developer updates the app to adjust the PRO version to look more like the regular version keyboard, as the Pro keyboard has an odd look to it. ### 5/5 — Marvelous - solves sad fact of consumer rejection of RPN *2015-12-11, version 2.3.1* ...but it has stopped working in latest iOS! We have no right to expect updates to freeware, but we can hope and pray for what we don't deserve. ### 2/5 — Doesn’t work in iOS9 *2015-12-03, version 2.3.1* Doesn’t work in iOS9, however it used to work well. The same developer has a newer app which is similar and does work in iOS9, so I recommend switching to that app. ### 5/5 — Need update *2015-11-29, version 2.3.1* Please, John. This is a 'must have' app for many of us. Now with IOS 9, it is non-functional. We NEED the update. Thanks. ### 4/5 — No longer works! *2015-11-23, version 2.3.1* No longer works crashes upon opening! ### 1/5 — Instant crash *2015-10-25, version 2.3.1* Under iOS 9.1 (the only version I’ve tried this with), the app crashes instantly when I press any function, including ENTER. ## Most critical reviews (10 lowest-rated) ### 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 ### 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. ### 1/5 — Calculator doesn’t work *2017-09-20, version 3.0* This no longer works with the latest iOS software. I paid good money which is now lost! ### 1/5 — It is not working any more *2015-12-10, version 2.3.1* Good product stop working. It crushes almost instantly in few strokes. Could you fix it, please ### 1/5 — Quit working after iOS 9.x *2015-11-29, version 2.3.1* The calculator no longer works. Is there a fix coming? Or can I get my money back? ### 1/5 — Used to be great, now crashes *2015-11-26, version 2.3.1* Crashes on opening. I used to use this instead of my HP 32sII. Now I have to carry it around. John, please fix this. ### 1/5 — Doesn't work with new iOS 9.1 *2015-11-13, version 2.3.1* This is (was) a good app but no longer works for me. ### 1/5 — iOS9 upgrade? *2015-11-10, version 2.3.1* Loved this calculator until it didn't work with iOS9 - hoping there will be an upgrade. ### 1/5 — Crashes *2015-11-03, version 2.3.1* I liked it until one day it just started crashing. ### 1/5 — Not working since iOS 9 *2015-10-26, version 2.3.1* This was my favourite rpn calculator app until iOS 9 and after. Whenever I press any button within the app, it closes. If an update is possible, it would be much appreciated. ## Most praised reviews (10 highest-rated) ### 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. ### 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. ### 5/5 — Cool little Calculator *2023-07-10, version 5.0* Works well on MacOS ### 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. ### 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. ### 5/5 — RPN! *2016-11-24, version 3.0* RPN! Need I say any more? ### 5/5 — Best iPhone 6 free RPN calculator *2016-04-23, version 3.0* Sweet little app for both portait and landscape HP calculator fans! ### 5/5 — Rpm *2016-01-09, version 3.0* Great app ### 5/5 — Excelente *2016-01-09, version 3.0* Excelente aplicación aunque esta ultima actualización se tardó años en llegar no importa ya que funciona de maravilla con o sin actualizaciones --- *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.*