# Kalkulilo (Calculator)

> Versatile calculator with scientific, bitwise, statistical, and time modes. (iPhone/iPad app by Alexander Clauss.)

- Source: https://appshunter.io/ios/app/kalkulilo-calculator/id286091993 (this page in markdown: same URL + `.md`)
- Developer: [Alexander Clauss](https://appshunter.io/developer/286091996)
- Category: Productivity, Education
- Price: $2.99 with in-app purchases
- Rating: 4.50/5 from 29 App Store ratings · 437 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.0 · 3 MB
- Languages: American English, German (Germany)
- Released: 2019-02-11
- Data updated: 2026-08-14
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/kalkulilo-calculator/id286091993/reviews.md

## What is Kalkulilo (Calculator)?

Kalkulilo is a comfortable calculator program and offers several different modes.

- The scientific mode offers all the usual functions and operations like the basic arithmetical operations, power, logarithm, roots, trigonometry etc. 

- The bit/integer mode offers logical operations (AND, OR, XOR, >>, etc.) on bit level. All values can be displayed as binary, octal, decimal or hexadecimal numbers. Calculations can be done in 8, 16 32 or 64 bits.

- In the statistics mode you can create a sample by adding several values and then calculate mean, median, quantil values, variance, standard deviation, range etc.

- Trigonometry mode provides lots of trigonometric functions, including legacy ones

- The base/radix mode allows you to do calculations with numbers of base 2 to base 36

- The Time mode lets you directly work with time values (hours, minutes seconds)

- A simple calculator is also included, with just the basic operators and large buttons.

The user interface can be customized, you can change the key colors for different categories of functions and operators which helps to distinguish and find these more easily. 


The App also includes calculator widgets for the homescreen which allows to do calculations directly from your homescreen and a calculator for the Apple Watch.

## Key features

- Scientific calculator functions
- Bit/integer mode with logical operations
- Statistical calculations
- Base/radix conversion (2-36)
- Time value calculations
- Customizable interface
- Apple Watch app and widget

## Pricing and in-app purchases

Base price: $2.99.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Remove Ads | $0.99 | one-time |


## What do users think of Kalkulilo (Calculator)?

Overall sentiment: positive

**Pros**

- 🚀 Excellent, powerful calculator
- 👍 Variety of modes and number systems
- 👍 Intuitive and easy to use
- 👍 Highly functional for engineers, programmers, and students
- 👍 Replaces physical scientific calculators

**Cons**

- 🐛 Stopped working after OS update
- 💰 Ads introduced after being paid app
- 👎 Buttons too small, hard to press
- 🔍 Confusing color scheme and UI

**Commonly reported bugs**

- Number doesn't transfer correctly when switching between modes
- Negative exponents not displayed correctly in engineering notation
- Loses calculation history when changing modes

**Most requested features**

- Add calculus, linear algebra, and probability functions
- Implement a 'repeated equals' function
- Add a backspace/delete button
- Allow customizing color scheme
- Improve Apple Watch integration

## Recent user reviews (10 of 437)

All indexed reviews: https://appshunter.io/ios/app/kalkulilo-calculator/id286091993/reviews.md

### 4/5 — Toller Rechner ohne Tastatursteuerung

*2026-07-10*

Es wäre schön, wenn ich - wie beim Apple-Rechner - die Eingabe über das Magic Keyboard meines iPads tippen könnte.

### 3/5 — Zufrieden,aber …

*2026-07-04*

Insgesamt positiv, eine Primzahlberechnung vermisse ich schmerzlich.

### 2/5 — New colors are terrible

*2026-07-02, version 6.0*

Not only are the standard colors now terrible, there is no option to revert back to previous patterns. You have to select individual groups of keys to change. And the options to change to are still terrible. My eyes hurt just looking at this.

### 5/5 — Excellent, stopped working on Apple Watch OS26

*2025-12-02, version 5.1.4*

I love this calculator for the ability to have some scientific calculation available on the Apple Watch. (Revised) It required a re-install after upgrade to watchOS 26 to have it work on my watch.
I particularly like the variety of modes and the ability to do math in any number system, not just binary, decimal and hexadecimal.
The size of the keys is also reasonably sized despite the functionality. I am basically using it as my primary calculator all the time

### 4/5 — Excellent, stopped working on Apple Watch OS26

*2025-12-01, version 5.1.4*

I love this calculator for the ability to have some scientific calculation available on the Apple Watch. However the app does not load on the Apple Watch Ultra 2 after upgrading to OS26 anymore. Still works fine on the iPhone under iOS26

### 1/5 — Crash with iOS 12

*2025-10-18, version 5.1.3*

Ver 5.1.3 crash with iOS 12 on iPod touch v6 too.

### 5/5 — Brilliant App

*2025-10-12, version 5.1.2*

Full suite of options, fast and reliable.

### 5/5 — Extremely functional

*2025-01-15, version 5.0*

Years after first finding it, this continues to be my default calculator on iOS. It’s easy to use, doesn’t push ads, and has any and every feature short of actual graphing that you might need to do some quick math.

### 5/5 — Calculator

*2024-10-24, version 5.0*

You should add a calculus calculator, linear algebra calculator, and probability. I love this calculator app

### 5/5 — Excellent rapport qualité-prix

*2023-01-07*

Pratique et performante !

## Frequently asked questions about Kalkulilo (Calculator)

### What kind of calculations can this app perform?

This app offers a wide range of calculation modes. These include scientific functions like powers and logarithms, bitwise operations for binary and hexadecimal numbers, statistical analysis for data sets, trigonometric functions, base conversions from 2 to 36, and direct time value calculations. A simple mode with basic operators and large buttons is also available.

### What are the different modes available in the calculator?

The app provides several specialized modes: Scientific mode for advanced math, Bit/Integer mode for logical operations on bits, Statistics mode for data analysis, Trigonometry mode for trigonometric functions, Base/Radix mode for number base conversions, and Time mode for working with time values. A basic calculator mode is also included.

### How can I remove ads from the app?

The app includes ads to support its development and to remain free for users. You can permanently remove these ads by making a small one-time in-app purchase. This purchase helps cover the costs of development and ongoing support.

### Is this app compatible with Apple Watch?

Yes, the app includes a dedicated calculator application for the Apple Watch, allowing you to perform calculations directly from your wrist. It also offers a calculator widget for the notification center on your iOS device for quick access.

### Can I customize the appearance of the calculator?

Yes, the user interface of the calculator can be customized. This includes adjusting the design and colors to your preference. The app also features colorized keys to help visually distinguish between different categories of functions and operations.

## Version history (last 5 releases)

### 6.0.3 — 2026-08-05

Fixes an issue when negating the result of a calculation ( for example to use the negated value for another calculation).

### 6.0.2 — 2026-07-09

- Bugfix:  When storing a number (which was directly entered and not the result of a calculation) to the memory it was not possible to immediately enter a new number. The existing number was extended instead. This is now fixed.

### 6.0.1 — 2026-07-08

- Better adjustment to the different rounded window corners under iPadOS 18 and older, 26 and newer and macOS
- On iPad and Mac it is now possible to make windows smaller than before.

### 6.0 — 2026-06-30

- Completely rewritten to support the latest iOS technology
- On the iPad you can use the App in windowed mode and even open multiple completely independent calculators at the same time
- There are several different Widgets for the homescreen available (a simple calculator, a scientific one and a bit/integer calculator)
- All keys which provide multiple modes can be either tapped to switch through all the available modes, or long-pressed to pick the mode from a menu directly 
- All other keys can be also long-pressed to display a more detailed meaning of the key, so when in doubt what a certain key is for, you can long-press it to find out. This feature can be also switched off in the settings if you don't need it.
- The "Engineering" mode now provides much more presets for the scientific calculator. There are modes for the common metric quantity prefixes (like nano, micro, kilo, etc)
- It's possible to copy the result into the clipboard and also paste in numbers and simple calculations (+, -, / , *, ( ,) )
- Via long-press of the "Exp" key you can directly enter one of the metric quantity prefixes, for example enter "1k" (kilo) instead of 1000 or "3m" (milli) instead of 0.001

### 5.1.4 — 2025-10-20

Fixes a small layout issue on the iPad

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## More apps by Alexander Clauss

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All apps by Alexander Clauss: https://appshunter.io/developer/286091996

## Related topics

[calculateretro](https://appshunter.io/ios/topics/calculateretro)

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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 2026-08-14.*