# RPN 30 — user reviews

> 31 indexed App Store user reviews of RPN 30 by Ashok Khanna, rated 4.70/5 from 154 ratings.

- Source: https://appshunter.io/ios/app/rpn-30/id1451413517/reviews
- App overview in markdown: https://appshunter.io/ios/app/rpn-30/id1451413517.md
- Rating breakdown: 5★ 128 · 4★ 14 · 3★ 8 · 2★ 1 · 1★ 3

## Newest reviews (10 of 31)

### 5/5 — Very nice

*2022-04-13, version 2.30*

What a relief to find a quality RPN calculator that works well across all my devices.  Be sure to long press the Help button to read the instructions.  This is now my daily default calculator when I don't have my 12C around...

**Developer response:** Not having my HP12C was the reason for making this calculator :) Thanks for the kind words and have a nice day

### 5/5 — Does the trick

*2022-02-26*

Nice and simple. No adds.

**Developer response:** Thanks!

### 5/5 — Fantastic

*2021-12-20*

Simple, clean and 100% free of detritus. No ads, no invasive privacy policies and extremely light weight. A class act all round.

**Developer response:** Thank you very much for the nice words :)

### 5/5 — Very good calculator

*2021-04-03, version 2.25*

I have a lot of experience using an RPN calculator and own several.  This is a nice app to have handy so I don’t have to go search for the more complicated ones in my collection.  My only complaint is that it took a bit of time before I figured out how to set the precision; it is in the Help menu, then how to escape the help menu.  That nitpicking is not a problem, just a comment.

**Developer response:** Thanks for the kind words :) Glad you like it. And yes, the initial discovery unfortunately takes a bit to get used to (for anyone reading this - hold down on the HELP button to bring it up and then flick it away to get rid of it). I agree 100% with you.

Unfortunately it was a trade off between guiding the user with more contextual help buttons / options. vs. using all screen estate for the calculator (I chose the latter).

### 5/5 — Great App

*2020-12-17, version 2.25*

It has all what I need, it’s easy and intuitive to work with.  Thank you.

**Developer response:** Thanks :)

### 5/5 — User friendly

*2020-11-20, version 2.25*

Love it!
Simple interface not crowded like some of these HP calculator replicas. A lot of functions available and you can customize your most frequent buttons!
Well done

**Developer response:** Many thanks for your kind note :) Have a nice day

### 4/5 — Looks great

*2020-06-23, version 2.0*

Simple and beautiful design.  Would be perfect if it had support for hardware keyboards.

### 4/5 — Refreshingly simple

*2020-05-16, version 1.25*

I echo all the comments made by other reviewers. 

Please consider making the alt function labels brighter, as I find them difficult to see in less than optimum lighting. 

Otherwise this is the best RPN calc I’ve come across. Thanks!

**Developer response:** Dear Alienpup,

Many thanks for the kind words! And also for the feedback.

The function letters were definitely too small. I have updated the App to version 2.0 — please try it and please let me know if it it is an ideal font size now :)

Best wishes,
Ashok

### 5/5 — Superb graceful RPN calculator

*2020-04-08, version 1.25*

Elegant and intuitive interface. 

Loads fast and looks great. 

I would make the following substitutions:

(1) Drop the radical, which can be achieved with 1/x and y^x

(2) Drop % and T% which are easily replaced with arithmetic operations. Maybe drop D% too although it's more useful. 

(3) Add the basic trig functions, at least sin and cos (with tan available as sin/cos). asin and atan would be helpful too, with acos available via asin. 

That would be 4 dropped and 4 added and a net improvement to the calculator adding capabilities that are really not available at the cost of modest conveniences.

**Developer response:** Many thanks for the review and feedback :)

Thanks for the comments, I agree with you on some of them. %D is my favourite function (since I’m always calculating how much something has increased or decreased), but I agree that % and %T are not useful enough to be included so I will replace them with Sin and Cos in the near future.

Also, I’d be happy to do a custom calculator for you with asin atan etc. and any other functions you want - just drop me an email at ashok.khanna @ hotmail.com. 

All the best and take care

### 5/5 — Elegant Programming

*2020-03-04, version 1.25*

Very nicely written app. I’ve been using RPN calculators for decades, and this is the best simple but robust calc app around.

**Developer response:** Many thanks :-) I will try to do more quality work in the future, and yours & others kind words is great delight and motivation for me

## Most critical reviews (10 lowest-rated)

### 3/5 — Huh???

*2024-08-22*

I agree with Talasoft guy. I went through engineering school using an HP 15 C calculator. I found this calculator too confusing to use. The developer might want to consider that people looking for an RPN calculator app are those of us who are familiar with RPN and don’t want to carry around a calculator anymore.  In other words don’t alienate the people who are most likely to use your app.  Furthermore, I am not sure anyone trying to learn RPN will make any sense to what’s happening on this calculator.

### 3/5 — Frustrating

*2022-08-23, version 2.35*

This is a great simple (and robust) rpn calculator. The navigation is smart, but not very intuitive. Needs more extensive, or easier to find, instructions.

**Developer response:** Sorry for your frustration. Press down on the decimal button “.” and then use your finger to drag the settings bar for number of decimals to the left or right. Let me know if any issues

### 3/5 — Looks good but… Deleted

*2022-03-13, version 2.30*

I’ve used RPN calculators for about 50 years, and while this one looks good on the surface I find the numbers being laid out in three distinct areas to be very confusing. 
RPN is all about a simple way to enter, manage and calculate numbers using a STACK. Three incongruent numeric display areas goes NOT a stack make. And where are simple things like Swap or Roll?
PCalc Lite is a much better RPN calculator because it gets the Stack right.

**Developer response:** Thanks for your feedback, that is valuable information. SWAP can be achieved by tapping the Y register in the top left of the screen and I will look into DROP further.

I get your viewpoint on the stack alignments, that’s just going to be a point of difference and I am glad you have found an App that works for you. My rational has been to treat the stack as a second class citizen where I use / forsee others to use the calculator with minimal stack manipulation (two reasons - 1. Do it right the first time and not worry about reviewing / editing the stack and more importantly 2. For any more complex calculations that require stack manipulation, I envisioned it would be better to use MS Excel or a computer).

Hence, my choice of display is to maximise the display size for the x register and make it more convenient with the y register + showing last expression.

Not to say I disagree with you, I completely understand your viewpoint, I guess mine is not as classical conformance to the notion of RPN calculators, as you alluded to in your review.

Thanks very much for your feedback and different perspective, I will ponder over it more. Thanks

### 3/5 — Close but not what I’m looking for

*2022-01-30, version 2.30*

Simple layout which is ok but the DIV button is off putting to me.  I ended up going for “RPN Calculator” which is a little better for my tastes. I’m switching from Android using “RealCalc” which has a little more HP like interface but still has larger buttons and multiple stack display. Wish they had an iOS port.

**Developer response:** Hi - sorry for late reply. I ended up taking your feedback on board and changed the DIV button. Thanks for suggesting it

### 3/5 — Average

*2021-08-15, version 2.30*

Interface needs work. Why “DIV” instead of “/“, when all other operators use their symbol ? Weird with number of places after decimal point. Etc.

I’m looking for something better.

**Developer response:** Thanks for the feedback and hope you find what you are looking for. I believe another popular model is Free42, perhaps try that one.

Thanks

### 3/5 — Thanks, Ashok. Still not working for me, though!

*2020-05-31*

Sideways and not fully rendered on iPad Air running iOS 12.4.5.
(No landscape view and keypad is not fully visible).

I have received a kind email from the developer, who notified me of the update. Unfortunately, when I tried to download it, I was informed it was not compatible, so I took the option to download the latest compatible version as prompted, hoping it might have been fixed at the same time.

Sadly, the problem has not gone away.

Although it is impossible to use, I have changed my review from 1 star to 3, on the basis of the kindness and effort this guy has put into producing what I'm sure will work well for anyone with the very latest iPad.

Dear Ashok; if you want to give me a brand new iPad, I'll happily test your latest version! ;-). Best Wishes. WS.

**Developer response:** Dear Whapper Stan,

Hope you are well. It took me a bit of time but I have created version 2.0 that now works very well for iPad.

I would much appreciate if you could try the new version and hopefully you will like it.

My best wishes,
Ashok

### 4/5 — The Store/Recall functionality is awkward.  The need to hold two buttons at once is clumsy.

*2024-10-03*

A generally smooth and uncomplicated system is not applied to the store/ recall implementation

### 4/5 — Need improvements

*2024-08-25*

I’ve been using a physical 42S and emulator on my phone for years. The down side is that the keys and display font are small. Apple default calculator app, on the other hand, have very large font and large key size, but it’s not RPN. This calculator here has the potential to be a great alternative to both, but it’s not (yet). 

1. Stack display is a bit confusing. Took me a while to figure out Y is on top left corner, and then the next 3 levels up on the right. It would be more consistent if you skip the top left corner position, and just have the stack on the right. 
2. While alternate functions are activated by long pressing the number keys/layer, in the advanced function keys/layer, it requires pressing ALT then another key. Why the different behavior?
3. Store/recall does not work at all.

### 4/5 — Awesome

*2024-08-16*

Nice and simple RPN calculator. If the font size of the stack numbers were bigger, it would be perfect.

### 4/5 — Nice clean graphic

*2021-02-13*

I find most of the RPN calculators too messy. I would prefer the divide function represented by the conventional symbol and the same stack as +-x.

The RPN calculator I really want is a direct adaption of the native IOS simple and scientific calculators (which are based on the physical Braun ET 22, designed in the late 70s, early 80s)

**Developer response:** Many thanks for the review and insightful comments. A couple of others also asked for the DIV as "/" and on the same row, but the issue is I have an oversized "ENTER" key so currently no space. I will keep thinking of this and let you know if an alternate approach works. I will definitely read into the Braun ET 22 - that's very cool stuff to know! I also really liked the native iOS calculator experience, hence this app (which as you said, is not a direct adaptation) :) Have a nice day.

## Most praised reviews (10 highest-rated)

### 5/5 — Love the streamlined operation

*2024-09-07*

Big buttons and smooth navigation across the pages.  You should apply your talents to make a better (similar) Watch experience.  All too crowded and clunky.

### 5/5 — Really good

*2024-03-17*

This is a really good RPN calculator, I couldn’t ask for anything more.

**Developer response:** Thanks!

### 5/5 — Perfect

*2024-01-21*

Couldn’t ask for a better RPN calculator for iOS

**Developer response:** Thanks!

### 5/5 — Great app for RPN

*2023-12-14*

The rpn app I had been using for years is no longer available, so I switched to this one. I’m glad I did; it’s very good. I had a question about using it and emailed the developer; he got right back to me with the information I needed. If you use reverse Polish notation, give this a try.

**Developer response:** Thank you very much :-)

### 5/5 — Best calculator on the App Store

*2023-11-14*

Does what it needs, doesn't beg you for money, stays out of your way and lets you calculate. 

Thank you so much!

**Developer response:** You are welcome :) Thank you for the kind words and using the app.

### 5/5 — Brilliant

*2023-08-27*

RPN30 is a fantastic implementation of RPN in an easy to understand and use calculator. The HP calculator emulators are good but can be too complex and have unneeded features for 90% of people's need. This will be my go-to everyday calculator.

### 5/5 — Simple, uncluttered, responsive

*2023-02-05*

Really nice simple RPN calculator app with a clean and uncluttered interface with decent sized buttons that nevertheless still has all the common functions I need on a handheld calculator. Responds instantly with no perceptible lag even on a fairly old phone. A few things in the UI are a little unintuitive at first (e.g. the location of the backspace, undo, and swap x<->y functions, and it took me an embarrassing length of time to figure out that you close the help page by swiping down), but it works well once you learn how to use it.

**Developer response:** Many thanks for the kind words. I agree that some of the UI is a bit hard to follow at first glance, sorry about that. Hopefully you will enjoy it for the years to come and that upfront time investment pays off :-)

Thanks again

### 5/5 — Engineering gem

*2022-10-27, version 2.40*

I have been using hp calculators with rpn notation since the 80s.
With the addition of the rectangular to polar  and polar to rectangular conversion feature added to this app. I really have no need for an actual physical calculator any more.
Thanks a bunch

### 5/5 — Very nice

*2022-05-22, version 2.30*

I first used RPN years ago on an HP calculator in college.  For the last five years off and on I’ve looked for an RPN iPhone calculator that was easy and quick to use, one that takes advantage of the iPhone touch environment, rather than one that tries to emulate physical buttons.  This calculator seems to do that.

### 5/5 — Absolute gem!

*2022-05-18, version 2.30*

I was just introduced to RPN, but unfortunately I couldn’t find any modern calculators with it. The old calculators that have it are now “vintage” and incredibly pricey, so I started looking for apps - and I’m glad I did, because this calculator is an absolute gem! It is elegant and clutter free. I have replaced using my iPhone calculator with this one. I love the fact that it has no ads. I would definitely pay for this. Thanks and keep up the good work! :)

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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 2026-06-10.*