# Calculi: Scientific Calculator — Unit & Currency Conversion > Smart scientific calculator with unit, currency conversion, and advanced history features. (iPhone/iPad app by Michael Natole, Jr..) - Source: https://appshunter.io/ios/app/calculi-scientific-calculator/id452182503 (this page in markdown: same URL + `.md`) - Developer: [Michael Natole, Jr.](https://appshunter.io/developer/443621043) - Category: Utilities, Productivity - Price: Free with in-app purchases - Rating: 4.40/5 from 374 App Store ratings · 17 written reviews indexed - Age rating: 4+ - Requires: iOS 17.6 · 43 MB - Languages: American English - Released: 2011-07-30 - Data updated: 2026-08-14 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/calculi-scientific-calculator/id452182503/reviews.md ## What is Calculi? Calculators can be hard to use. Calculi plans to change all that. SIMPLE BUT POWERFUL Calculi is a smart calculator that is simple and easy to use, but with advanced features for power users. Whether you are trying to balance your checkbook or taking an advanced math class, this app will help you with all of your calculating needs. CALCULATE ANYTHING Calculi doesn’t just add two numbers together but can solve complex expressions using the order of operations. The multi-line display allows for small or large expressions. So go ahead and calculate anything and everything! Press the 2nd button to reveal more scientific functions. UNIT CONVERSION You can easily convert any of your calculations to a different unit across 17 categories such as length, area, and volume. Unit conversions are saved to your calculation history for easy review. A Calculi Pro subscription is required for this feature. CURRENCY CONVERSION Traveling abroad? Not sure how much your lunch costs? Calculi has you covered with support for over 30 different currencies around the globe (data is updated daily from the European Central Bank). A Calculi Pro subscription is required for this feature. CONSTANTS Common constants from both mathematical and scientific fields (astronomical, chemical, electromagnetic, etc.) are included for use in calculations. DESIGNED WITH iOS 18 AND iPadOS 18 IN MIND Calculi adapts to all the latest iOS and iPadOS devices. Even better, multitasking and multi-window support is available in all orientations on the iPad. Interactive widgets are included for calculations on your home screen, and Control Center widgets provide quick access. You can have Calculi wherever you need it. GESTURES Gestures are fun. So why not? - Long press the delete button to clear the display - Long press the equals button to use the previous result or expression - Long press the display to copy, paste, or share - Long press any calculation item to reuse the expression or result SUPERCHARGED HISTORY TAPE Calculations from the history tape can be bookmarked for later and notes can be added for additional context. You can search across notes, expressions, and answers to find the calculation that you are looking for. GET SHARING Don’t be selfish. This history tape can be shared either as a single thread or the entire tape using numerous methods such as email, messaging, or print. There is also an iMessage app so you can easily send calculations. CALCULATE ON YOUR WRIST Calculi is also available on Apple Watch! Besides a four-function calculator, you will also find a tip calculator and counter. EXTERNAL KEYBOARD AND TRACKPAD SUPPORT Pair an external keyboard or trackpad to gain access to powerful shortcuts and full cursor support. You can hold down the command key on your keyboard to view all the available shortcuts. Finally, if you enjoyed Calculi, please take some time to leave a review. Feedback is always appreciated for future updates. CALCULI PRO This yearly subscription grants you access to the following: - Unit Conversions - Currency Conversions - App Themes - Colorful custom icons TIP JAR If you enjoy using the app and want to support an independent app developer, please consider sending a tip. Subscription Details – Payment will be charged to iTunes Account at confirmation of purchase – Subscription automatically renews unless auto-renew is turned off at least 24-hours before the end of the current period – Account will be charged for renewal within 24-hours prior to the end of the current period, and identify the cost of the renewal – Subscriptions may be managed by the user and auto-renewal may be turned off by going to the user’s Account Settings after purchase Terms of Use: https://www.calculiapp.com/terms.html Privacy Policy: https://www.calculiapp.com/privacy-policy.html ## Key features - Complex expression solving - Unit conversion (17 categories) - Currency conversion (30+ currencies) - Scientific constants - Supercharged history tape - iMessage app integration - Apple Watch app ## Pricing and in-app purchases Base price: Free. **Subscriptions** | Subscription | Price | Period | | --- | --- | --- | | Calculi Pro | $2.99 | per year | **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Small Tip | $0.99 | one-time | | Medium Tip | $2.99 | one-time | | Large Tip | $4.99 | one-time | ## Recent user reviews (10 of 17) All indexed reviews: https://appshunter.io/ios/app/calculi-scientific-calculator/id452182503/reviews.md ### 5/5 — WAY better than the stock iPhone calculator! *2024-03-16, version 4.3* This calculator app blows the built in iPhone one OUT OF THE WATER!!! (iPhone 11). For me at least it’s better in many ways, one of the most important of which is the history screen including the functions of bringing past answers & expressions into your current operation. Also, despite it’s age the author regularly drops helpful updates. This is coming from someone who generally, highly prefers native apps over 3rd party ones. ### 1/5 — Pop up’s *2023-01-05, version 4.0* I really don’t need a pop up rating request every time I open the app ### 2/5 — Updated to add ads? *2022-12-10, version 4.0* You updated the app to have ads? That’s so disappointing! I also don’t like the added clutter of keys I will never use in the iPad app which forces the number keys to be centered instead of on the left as one would expect. I would have to limit my use to slide over in landscape orientation to keep the normal calculator feel. ### 5/5 — Awesome app! *2022-10-14, version 3.6.1* Using it all the time, very helpful calculator. ### 5/5 — Almost Perfect *2021-07-24, version 3.4.1* This is dang near perfect: works with a keyboard! Works in Split Screen! No ads! Data not linked to your identity! History tape, keyboard shortcuts, shareable history… seriously, almost everything I want. There’s just one thing that makes it impossible for me to use: It doesn’t work in Slide Over. You can use the calculator itself in Slide Over, or you can view and share the history, but you can’t do both. Once you view the history, there’s no way to get back to the calculator in Slide Over, you must change to Split Screen, or close and re-open the app, that kind of thing. If this app ever gets Slide Over fixed, I will certainly download it again and definitely update my review. Until then, might as well delete it and keep using the calculator on my iPhone while working on the iPad. For what I’m looking for, this app is unusable. UPDATE: This app is working perfectly now! I love it! The developer fixed it in the latest update, and I can confirm that now it works in Slide Over. It went from being unusable to being exactly what I want. Seriously, if I had the talent to be able to develop apps, this is what I would make—it checks all the boxes for me. I don’t need scientific functions or anything fancy, but I do need a history tape. I really like the tape in this app, because each equation has it’s own “bubble” in the history tape window, which makes recognizing each one simple. I kind of can’t wait for my friends to ask me if I use a calculator app on my iPad, so I can recommend Calculi to them and tell them about all the reasons they’re going to love it, too. ### 5/5 — Great ui desing *2021-05-18, version 3.3* Great app and great design, loving it ### 1/5 — Please add option for Dark Mode all the time *2020-12-06* The best iPad calculator there is (and I’ve tried them all!) Super lightweight, no bloatware, works with keyboard and has a history tape! What more could you want?!? Please add option to have Dark Mode on all the time (I also preferred the old icon so an option to choose icons would also be *really cool*) ### 5/5 — This is a great calculator app *2020-10-18, version 3.2.1* Best calculator app it replaces my old one ### 5/5 — Nice *2020-08-09, version 3.1.1* Nice ### 3/5 — It calculates, but the history is buggy *2020-06-21, version 3.0.1* When I open the app and make a calculation, it does not appear in the history. If I go back to the home screen and then return to the app, my previous calculation now shows. When I do the next calculation, it replaces the info in the top tile instead of adding a tile. On the next calculation, things start working as they should. This is the pattern every time I clear the history. I would give this app 5 stars if not for the buggy history. Without that feature it is a decent calculator, but then it is just a calculator. Please fix it for a great app! ## Frequently asked questions about Calculi ### What does Calculi do? Calculi is a smart calculator that simplifies complex calculations. It offers advanced scientific functions, allows for solving complex expressions using the order of operations, and provides a multi-line display for large inputs. It also includes features like unit and currency conversion, constants, and a history tape. ### What are the key features of Calculi? Key features include the ability to solve complex expressions, unit conversion across 17 categories, currency conversion for over 30 currencies, access to scientific constants, a supercharged history tape with bookmarking and notes, and integration with iMessage and Apple Watch. It also supports gestures and external keyboards. ### How much does Calculi cost? The base Calculi app is free to download and use for its core calculator functions. However, advanced features like unit conversion and currency conversion require a Calculi Pro subscription. Specific pricing details for the subscription can be found within the app. ### What devices is Calculi compatible with? Calculi is designed with iOS and iPadOS in mind and adapts to all the latest devices. It offers multitasking and multi-window support on iPad, interactive home screen widgets, and Control Center widgets for quick access. It is also available as an app for Apple Watch. ### What are common use cases for Calculi? Common use cases include balancing checkbooks, solving problems in advanced math classes, converting units for measurements (like length or area), converting currencies while traveling, and using scientific constants in calculations. Its history tape also allows for easy review and sharing of past calculations. ## Version history (last 5 releases) ### 4.4.1 — 2025-03-04 This update includes a customer center to manage your Calculi Pro subscription. ### 4.4 — 2025-01-13 This new release for Calculi contains the following new features and improvements: - A revamped calculation history that allows you to add notes, bookmarks, and search calculations. - Updated home screen widgets to support light, dark, and tinted modes. - New large scientific calculator widget on iPadOS. - Control Center widget for quick access to Calculi. - Updated light, dark, and tinted icons support. - Support for iOS 18, iPadOS 18, and watchOS 11. - Removed ads. - Other bug fixes and improvements. ### 4.3 — 2024-02-26 In this latest release, Calculi now includes interactive widgets for your home screen! Additionally, you will find the following features and improvements: - Support for iOS 17, iPadOS 17, and watchOS 10 - All new Apple Watch app - Option to speak actions and results - New alternative app icons for Halloween, Thanksgiving, Christmas, Fall, and Winter - Support for home screen quick actions ### 4.2.2 — 2023-08-15 This update fixes an issue that could cause the app to crash. ### 4.2.1 — 2023-08-15 This update brings general performance improvements. ## Apps similar to Calculi | App | Rating | Price | Category | | --- | --- | --- | --- | | [Calculator +](https://appshunter.io/ios/app/calculator-plus/id351815470) | 4.6 (9,595) | Free | Utilities | | [Calculator #](https://appshunter.io/ios/app/calculator/id458535080) | 4.6 (35,876) | Free | Utilities | | [Haseba Calculator](https://appshunter.io/ios/app/haseba-calculator/id1121281655) | 4.6 (3,795) | Free | Utilities | | [Calculator₊](https://appshunter.io/ios/app/calculator/id398129933) | 4.7 (1,726,271) | Free | Utilities | | [Calculator +ㅤ](https://appshunter.io/ios/app/calculator-plus/id1597933199) | 4.6 (4,519) | Free | Utilities | | [Basic Calculator: Classic Calc](https://appshunter.io/ios/app/basic-calculator-classic-calc/id430271248) | 4.8 (3,164) | Free | Utilities | ## More apps by Michael Natole, Jr. - [Profit Finder: Fee Calculator](https://appshunter.io/ios/app/profit-finder-fee-calculator/id1114881855) - [Margin Finder: Sale Calculator](https://appshunter.io/ios/app/margin-finder-sale-calculator/id1471927151) All apps by Michael Natole, Jr.: https://appshunter.io/developer/443621043 ## Related topics [scientific calculator calculus](https://appshunter.io/ios/topics/scientific-calculator-calculus) --- *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 2026-08-14.*