# Calculator & Unit Converter — user reviews > 50 indexed App Store user reviews of Calculator & Unit Converter by CAT VIET SOFTWARE DEVELOPMENT & MEDIA JSC, rated 3.61/5 from 28 ratings. - Source: https://appshunter.io/ios/app/calculator-and-unit-converter/id442665708/reviews - App overview in markdown: https://appshunter.io/ios/app/calculator-and-unit-converter/id442665708.md - Rating breakdown: 5★ 15 · 4★ 2 · 3★ 3 · 2★ 1 · 1★ 7 ## Newest reviews (11 of 50) ### 5/5 — Cannot go wrong *2013-01-26, version 4.6* I was looking for a calculator that would support RPN. I downloaded a couple that claimed to work on RPN and was disappointed to find that the developers did not seem to know what RPN is. To boot, this calculator may take over several other apps that I regularly use as a professor in engineering. I recommended the app to my children's middle school math teachers. For a dollar this app does more than what they need. Even if not quite as complete as some of the advanced calculators, the kids are not getting any more for the additional $130... ### 5/5 — Great FREE calculator *2012-12-24, version 4.5* I really like this app - I have tried many other free calculators, and they all have either blocked functionality or they run ads and nag you with pop ups. Not only does this app not do any of that, it has far more functionality than most of the other calculators I have tried - the graphing feature, works quite well. It also integrates and differentiates. A great calculator app. ### 5/5 — ALL THE CALCULATORS YOU'LL EVER NEED IN ONE APP *2012-12-02, version 4.3* All the calculators and features you will ever need in one application. Basic, scientific, graphing and statistics calculators, equation solver, base conversion, date and time and finance calculators. The unit converter has an incredible array of units, including shoe, sock and shirt sizes. Did I say it also has a tip calculator? For those who need a printing calculator, you can access input history, that you can reuse and edit. If you work with formulas, there is an optional in-app purchase for 800+ formulas. This app has a mind-numbing array of features. If you're a rocket scientist, you may need some other special calculator, but for all the rest of us; if you have this calculator, you will never ever need another one. ### 5/5 — Absolutely Amazing *2012-10-18, version 4.2* I paid $1.00 for a simple calculator to get rid of adds. I upgraded this one for $1.00 and look at what you get. Please check for yourself. There is to much to sit and try and tell you all of it. There is a converter here with 113 separate items in it. I use capacitance and resistance daily and their included. No more moving decimal points. So simple to use. There are time conversions. Put in 2 dates and get the time between them. Put in dates and it will count down and alarm when it reaches them. World clocks. Biorhythms. I am thrilled about an app that will be used at work. It will make things so much easier. ### 4/5 — More than expected, with a little crash thrown in. *2012-09-25, version 4.2* I can't believe how many things this app does, unfortunately since the last update, it has started to crash every time I try to email from the app. Hit the email button, and crash...even when I used the feedback option. This is a great app that I had rated 5 stars. Fix the email, and I'll put the fifth star back. ### 5/5 — Great App *2012-09-01, version 4.1* Love the calculator. Well worth the money! Stop watch needs to run in the background. Would like to be able to add more time zones when using the world clock and have an alarm clock. With the additions mentioned, there would be no better app on the market. Keep up the good work! ### 5/5 — Found it works fine! *2012-08-31, version 4.1* After reading 2 reviews that said the "Full" version crashed, I downloaded the free version. After testing that one out, I decided to chance it and purchased the $0.99 full version. It works fine just like the free version. All I can say is MAYBE those two folks had reached the limit of their storage capacity or perhaps they had dropped their iPad more than I have. At any rate I have the "New" iPad and 64 gig of storage. This full version works just fine. Well worth the .99 cent download! ### 5/5 — PHENOMENAL *2012-07-23, version 4.0* Simply put, there is no better calculator available for the iPad. There are barely better calculators available in calculator retail stores. From the most basic math to the most complex trig and every formula in between this calculator has you covered. PPCLINK knocked this one out of the park. If you need a calculator for your iPad you should stop searching, download Calculator Pro, and move on to your next equation. ### 4/5 — Great, except... *2012-05-14, version 4.0* I'm in high school taking calculous and this calculator is great for me. But its not the only calculator I use unfortunately. The one thing you fall short in and I need before I give it 5 stars is a table of values for the graph and an improved graph in general. If you can make navigating a bit smother too it would help. The calculator I used previously had it while having much less creativity than this one. You guys need to step back a second from skins and versatility and focus on perfecting what you already have. Till then you have 4 stars and second best from me. ### 5/5 — Awesome update! *2012-05-12, version 4.0* The update is wonderful. I was disappointed to find I am unable to add the periodic chart to the quick launch menu. Was the omission of the periodic table and the biorhythm calculator from the quick launch menu just an oversight that might be fixed in an update? :) ### 5/5 — INCREDIBLE!!! *2012-05-12, version 4.0* This is my favorite app so far. This app has everything you could possibly need, assuming you not a rocket scientist or astro physicist. I use it at least 3 or more time a day. My kids use it as well for their homework. I highly recommend it to anyone that is looking for a ..... well, a mathematical anything! (Not fair, or correct to call it just a calculator.) ## Most critical reviews (10 lowest-rated) ### 1/5 — Currency convert bug *2019-03-21, version 5.8* The currency convert bug remains 😔 ### 1/5 — bio rhythm problem *2017-08-09, version 5.7* when switch to bio rhythm that interface not show probably, and could not switch to other function. ### 2/5 — I upgraded from the previous version and added, or tried to, the optional biorhythm, *2013-01-20, version 4.6* I upgraded to the new version hoping it would be an improvement but....... I tried adding the free skins, the biorhythm chart and periodic table, unfortunately these don't work. I tried the "contact us" from the menu and that didn't work either. Pretty disappointed especially since one of the additions cost me. Hope they fix this. ### 2/5 — 12 In 1 Scientific Calculator's Clock... *2012-12-14, version 4.4* I thought, "An ideal Scientific Calculator", but then, the Time and Date (World Clock) feature went nuts! It was doing fairly well, but then, the Seconds Hand began "ticking" at a rate of about 5 seconds in 1 second! It gains about 5-7 minutes in about 2 minutes! Absolutely useless as a time keeper. Otherwise, 5 stars! However, if the clock isn't accurate, how can I know if other features are accurate? Until this is fixed, sorry, but only 2 stars. And, why not make it a digital set of clocks. Very disappointed in this App! Fix this problem, and I will gladly rate it 5 stars! Thanks, Aggie1 ### 3/5 — Crashes on 14.3 *2020-12-28, version 5.8* Was great now always crashes on launch ### 3/5 — Bummed *2019-06-02, version 5.8* I have used this calculator for years. Very disappointed that when I finally needed the mortgage calculator that I can’t print or share the amortization table. Reason for dropping my review. Great calculator other than that. ### 3/5 — Skin pack *2018-05-11, version 5.7* Skin color orange doesn't work. Only reason I bought this calculator because it reminded me of LCARS. Please fix and yes I bought the skin pack. ### 3/5 — Mostly very good *2012-06-12, version 4.0* The majority of what I've seen of it so far is very good. I like being able to use parentheses to group and order formulas. The date calculator was, however, incorrect in the first calculation I tried - from my birthday until today. The answer was wrong by three days. It also showed 0 hours and 0 minutes but I don't see that as a big problem. Also in the date calculator section, there is a "Add/Subtrack" option. That is spelled wrong - it should be "Add/Subtract" ### 3/5 — Equation Solver only solves polynomials *2011-11-29, version 2.8* I want to give this app 5 stars, but it's equation solver functionality only solves polynomials. As a physics teacher, this is a huge limitation as nature expresses itself mathematically in many ways beyond polynomials. Additionally, the simultaneous equation solver only accepts linear equations. These limitations force my students away from this app and back to their TI calculators...and that's a shame. Please update this app and make the equation solver much more robust. You'll get 5 stars from me and advanced students of science and math will be more likely to buy and use it. ### 4/5 — Very nice app, conversion selection rather confusing *2013-10-28, version 4.8* My go-to calc app now, though I was initially confused by the conversion selection panel. Took a long while before I realized that I could actually select multiple units and convert among them instantly. Also, rvs160 is mistaken, in that kilo/mega/etc. prefixes are technically restricted to the decimal (base 10) world. The XXbi- prefix standard (kibi/mebi/etc.) for base 2 counting is at least 15 years old, and is correctly implemented by the author in the conversion panel. ## Most praised reviews (10 highest-rated) ### 5/5 — “Go-To” For everything! *2022-03-22, version 5.8* I am a self-taught Astrophysicist, Astronomer, and Rocket engineer (simulated). I searched a long time, through a ton of different software to make unit conversions or specific mathematic formulas, easier. I then found 12 in 1 Calculator. Very intuitive design, and has such an incredibly versatile library. I really enjoy reading my biorhythm statistics! I recommend this if you’re anything like me, I love chemistry, geometry, math, mechanical engineering, (coding soon). I do it all, and 12 in 1 has it all! ### 5/5 — The best at conversion *2021-08-10, version 5.8* Better than any I’ve tried. Includes virtually every option. ### 5/5 — Absolute Best All Trade Calculator for iPad! *2019-02-07, version 5.8* You won’t find anything to come close to handle whatever calculation you need!, Thank you!! ### 5/5 — The Best iPad Calculator! *2018-12-02, version 5.8* This is a great app, you don't need any other calculator at all and it takes full advantage of iPad's HD. Plenty of tools. The best deal for the price! ### 5/5 — Just perfect *2017-08-31, version 5.7* There is so far no better investment I have made on the App Store, I've been an apple user for 8+ years and this is my very first review I've written. I am yet to encounter any problems and if you are either in college or financing this calculator is perfect for you. Personally, I'm in college and I seriously doubt that I will ever encounter an equation that this calculator cannot handle. 10/10 ### 5/5 — Significant information, quick to fix *2017-05-30, version 5.6* I am impressed by the response of the team. I found a small glitch, reported it and received an email within a day. They quickly fixed the problem plus a few more I had not noticed. Well designed format. ### 5/5 — Terrific app UPDATED *2016-10-02, version 5.3* UPDATE: iOS10 initially disabled this calculator, but the developers have made it whole again, including the currency converter (which, alas, doesn't work on the iPhone version.) That said, this is the best iPad calculator I've found. ORIGINAL REVIEW: I can't imagine needing any other calculator. I use it mostly for unit conversions and a little for statistical functions, taking advantage of a tiny fraction of its capability. This calculator is intuitive, very easy to navigate and use. Highly recommended. ### 5/5 — Still one of the best calculators. *2015-01-07, version 5.0* Covers many useful functions with input arrangements arranged for the function being calculated. The inclusion of a periodic table complete with element descriptions and videos explaining many of the elements. Cover conversions, time, statistics. It will even figure your tip for self or numbers of eaters. ### 5/5 — Great App! *2013-04-14, version 4.7* This App functions perfectly. I've had it for about a year and have never had any problems with it through with any of the iOS upgrades. If you need a multi-function calculator that works, I recommend this App! ### 5/5 — Love It *2013-02-12, version 4.6* I loved the free version so much, I upgraded to the pro version to, in part, support the developer. I appreciated that the free version had no ads, which made my upgrading feel more sincere. Additionally, I'm glad I did! This version is PACKED with features! I particularly like the date/time calculator since this helps me in my business, which is the other reason I upgraded. I also perused through the app and saw many other features that I didn't originally know about, but was glad to discover. And, after months of use, I'm still discovering features! Great job! --- *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.*