# allRPNCalc Calculator — user reviews > 53 indexed App Store user reviews of allRPNCalc Calculator by Ernest Brock, rated 4.90/5 from 59 ratings. - Source: https://appshunter.io/ios/app/allrpncalc-calculator/id289555909/reviews - App overview in markdown: https://appshunter.io/ios/app/allrpncalc-calculator/id289555909.md - Rating breakdown: 5★ 55 · 4★ 2 · 3★ 2 · 2★ 0 · 1★ 0 ## Newest reviews (17 of 53) ### 5/5 — Glad to see the update! *2020-08-20, version 4.2* I have been using this RPN calculator for a number of years and I love it! Great for engineering calculations, conversions and financial. This is a great product for a die hard engineer that grew up on RPN! Thanks for keeping it going! ### 5/5 — Excellent Calculator *2020-07-28, version 4.2* Once you’ve learned RPN, you can never go back. This calculator is very easy to use and super reliable. If you know RPN, you’ll be very happy. If you want to learn, this calculator is a great reason to make the jump. ### 5/5 — Great calculator ! *2020-06-19, version 4.2* I’ve been using this app for years, ever since I lost my HP41. I only got it as a temp, but it quickly became full time. If you like using RON, you can’t beat it. Plus, it’s got a lot of features my old HP didn’t. I find the conversions very helpful (cu yds - cu in, km - mi, etc) ### 5/5 — Awesome RPN calc *2020-02-11, version 4.2* I’ve been using this app for quite a while and love it!! Thanks! ### 5/5 — Love this app *2019-10-21, version 4.2* Really nice if you’re used to RPN calculators. I use it daily. ### 5/5 — AllRPNCalc *2019-06-16, version 4.2* For my needs, this is the best rpn app I’ve used. ### 5/5 — Super duper awesome in all the right ways *2019-05-17, version 4.2* Comprehensive features, intuitive settings, and a natural user interface. Well thought out and developed calculator. Thank you! ### 5/5 — Outstanding RPN calculator... *2019-03-12, version 4.2* If you like HP calculators, this app should serve you well. I have been using this calculator for years, and it remains one of my all time favorites. It takes a successful HP calc and adds several useful features: unit conversions, currency exchange rates. I also value its ability to perform scientific and financial calculations. I have tried and used more than 20 calculator apps. Some do offer features not in this one. However, it is in my top two calculator apps. So glad the developer has updated this app to be compatible with current iOS versions. Hope other legacy app developers will do the same. The fear of losing this one kept me from being willing to update to the latest iOS. UPDATE: Been using this great app for years, and it never lets me down! Kudos to the developers who have kept this app working throughout all the many iOS changes by Apple. ### 5/5 — Best one *2018-06-29, version 4.2* Does it all, excellent interface and operations ### 5/5 — User *2018-06-27, version 4.2* I like this implementation of RPN. Would be nice if there were a native iPad version — that somehow took advantage of the larger screen. ### 5/5 — Hp-12c +++++ *2018-05-23, version 4.2* For those of us who grew up using Reverse Polish Notation, RPN is built into our hand. This little calculator app is easy to use, and has many more features than the HP-12C. Weight and volume conversion is often really useful, and it's easy here. Currency conversion! Get updated conversion rates with a couple taps. I've been using this great app for about 7 generations of iPhones. ### 5/5 — allRPNCalc is best one out there *2018-04-26, version 4.2* I've tried most of the HP calcs for iphone. This is the most intuitive interface and includes super helpful conversions, including currencies. Love it. Thanks for updating!! ### 5/5 — allRPNCalc - the best *2017-11-23, version 4.2* I have bought very few apps for my phone. The purchase of allRPNCalc is the exception. I spent a few dollars on this several years ago and it is the best use of money for an accessory ever. A powerful RPN calculator, that does everything I need and more. It is regularly updated to keep it in sync with all the updates iOS undergoes. I highly recommend this app to anyone that needs an RPN calculator. You will not find better. ### 5/5 — Great RPN calculator *2017-10-21, version 4.2* I use it all the time! ### 5/5 — Great RPN calculator! *2017-10-15, version 4.2* I used to work for the HP calculator division that pioneered RPN. Trust me. This is beyond a full featured RPN machine. Well thought out. Great job! Each version is even better than last. Now at v4.1. Very happy customer. ### 5/5 — Excellent *2017-10-12, version 4.2* Been using for years. All the functionality plus more. Never a crash. ### 5/5 — Great RPN Calc! *2017-10-12, version 4.2* Calculations are spot-on and this developer has been kind enough to provide free updates for many years now... Which makes it well worth buying. I've tried others and I still like this one the best. Very easy to use yet it has the depth and breadth you'd expect. I use it frequently for mortgage calculations and amortizations. ## Most critical reviews (10 lowest-rated) ### 3/5 — Not for iPad *2020-08-22, version 4.2* The description says it is optimized for iPad but it’s not. The display is fixed for portrait, does not fill the screen and looks fuzzy. I uninstalled and will try to get a refund. ### 4/5 — Overall most functions work and some don’t work. *2024-09-10* I have tried to contact the technical support person for this application about several issues and have not heard back from him. The currency exchange converter is not working properly for a number of currencies such as Swiss francs (CHF) to US dollars. Negative numbers are miss handled and miss calculated going from Prog mode to Math mode. This application needs to reverse engineer how to handle negative numbers from the HP 16C calculator. In statistics mode when a logarithmic plot is made with a correlation of better than 0.999, the x axis approximation is severely miscalculated when the X,R button is pressed. Try this for yourself. The y axis approximation works nicely for the logarithmic curve plot. In the short time frame that I have been using this application I have found these issues. Most other features and functions are working perfectly well. There is probably more features that are not working which may make for another review by someone else. Overall this is a good application to experiment with and is worth the six dollars. ### 4/5 — Works great, except *2018-01-08, version 4.2* I’ve been using this app for many years and find it great as a financial and general calculator. I calculate loan payments routinely. It has always worked great. However , recently I looked at an amortization chart and could not exit the chart. Stopping and restarting the app did not clear it. I had to restart iOS to get back to the main page. Please fix! **Developer response:** Charlie- To get out of the Amort Table just touch the Done button in the lower left corner of the display. To learn how to use the Amort Table, touch the ? key followed by the Amort Table key. If you think there is still a problem, please contact me directly. Touch the circle i icon in the left side of the display, then touch the About tab and select the "Contact tech support" button and send me the details. I hope this helps. Sincerely, Ernie Brock Developer ### 4/5 — Very very good Calculator *2008-09-14, version 0* (14-Sep-08) If you prefer the RPN entry method you will like this calculator. The keyboard layout makes sense and the functions are well organized into separate menus. Switching display modes is simple, for example, to select "4 decimal places fixed" simply press the display mode indicator at the upper left until it reads "Fix" and then press "4." You can view the contents of all registers (except the triangle solver) via the help menu icon. Key clicks can be turned on or off for quiet locations. The unit converter is intuitive, making good use of the iPhone/iTouch UI methods. And... the factorial (gamma) function operates correctly, with "-0.5 n!" giving the proper result... many calculators get it wrong or throw an error. This app gets nearly everything right. Some minor cleanup of the look (move the help button to top center and extend the static number & four-function keys) and a 64-bit capability in the programmer's functions will merit a perfect 5 stars, but really: for a first release this is superb. ### 5/5 — Love this Calculator *2023-12-07* Had to have an RPN calculator, and this one has zero downsides. It like every HP in one. The developer is attentive to keeping it up-to-date with ios changes. ### 5/5 — Still the best RPN Calculator app out there! *2023-11-06* I grew up with an HP 35 and moved to the 11c. This app is superior to HP. So much more capability and usable functions. I have been using this RPN calculator since it came out many years ago and I love it! Great for engineering calculations, conversions and financial. This is a great product for a die hard engineer that grew up on RPN! Thanks for keeping it going! ### 5/5 — Best RPN Calc *2023-01-21, version 4.2* I grew up using the HP42s, which I loved. I have the phone app for the HP42 also but I use this app as my go to app. Easy to use with all of what I need within a few strokes. ### 5/5 — Better than HP! *2022-08-05, version 4.2* Didn’t think I’d ever say this, but this calculator is better than HP’s. Of course, it doesn’t have all the cool stuff built into a 15, for example, but for what it does it’s very thoughtfully designed and works conveniently well. I also like all the trivia and background sprinkled throughout the documentation, FAQ, etc. Not only is this a very well-designed and useful calculator, but it also educates you on some of the history and science behind implementing floating point math in a binary machine. I’m a very happy customer. ### 5/5 — Awesome *2022-04-25, version 4.2* Best smartphone calculator out there! ### 5/5 — Love the app *2022-02-09, version 4.2* Really nice app. Does a very good implementation of RPN, and has numerous useful functions. I use it every day. ## Most praised reviews (4 highest-rated) ### 5/5 — The best!! *2021-11-07, version 4.2* Hands down, the best calculator anywhere. If you’ve ever used an RPN calculator this is the one you need. If you haven’t used an RPN calculator, you should learn so you can use this one. Absolutely the best. ### 5/5 — Great RPN calculator! *2021-07-18, version 4.2* Beautifully implemented, with all the usual functions and many unexpected bonuses (e.g., currency conversions, 12c-like financial functions, stat plots with regression lines, etc.) ### 5/5 — Go-To Calculator *2021-06-12, version 4.2* A super all-in-one tool. I’ve used it every day for years. The conversion tool is especially helpful. ### 5/5 — Best and most comprehensive financial calculator on the market *2020-09-10, version 4.2* Highly recommend --- *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.*