# Dentaku: Musical Calculator — 200+ Tones, Piano & RPN Calc

> 200+ Tones, Piano & RPN Calc (iPhone/iPad app by Shinji Koki.)

- Source: https://appshunter.io/ios/app/dentaku-musical-calculator/id6476873490 (this page in markdown: same URL + `.md`)
- Developer: [Shinji Koki](https://appshunter.io/developer/1728035397)
- Category: Utilities, Music
- Price: Free
- Age rating: 4+
- Requires: iOS 15.0 · 25 MB
- Languages: American English, French (France), German (Germany), Italian, Japanese, Korean, European Portuguese, Chinese (Simplified, China), European Spanish, Chinese (Traditional, Taiwan)
- Released: 2024-02-04
- Data updated: 2026-05-18
- User reviews in markdown: https://appshunter.io/ios/app/dentaku-musical-calculator/id6476873490/reviews.md

## What is Dentaku?

In 1981, the German music group Kraftwerk released a song performed on a calculator. The title of the song is "Pocket Calculator" and the Japanese version is titled "Dentaku" (which means calculator in Japanese).

At the time, Japanese calculators were at the peak of their evolution, and it was not uncommon to find models with musical scales assigned to each button, allowing users to play music.

I created this app to celebrate those nostalgia-filled days and to bring a little joy to daily calculation tasks. This app is designed not only as a practical tool but as an experience to be enjoyed through the senses.

Features:

• A musical scale is assigned to each button and even between buttons, producing beautiful sounds as you operate it. You can select from 200 different tones.

• The position of the notes can be easily checked using the "Show Musical Scale" option. (C, C#, D, D#, E, F, F#, G, G#, A, A#, B...)

• Choose your favorite background color. The color changes dynamically based on your tapping speed and gradually returns to the base color when you stop. The transition depends on the original color; for example, a blue background will take on a reddish tint as you tap repeatedly.

• In "Auto Mode," the background color and tone change randomly, keeping every calculation fresh and exciting.

• Save your favorite combinations of tone and color as "My Themes" to recall them at any time.

• While basic functions are based on the standard iOS calculator, unique refinements have been added.

• By default, it uses "Order of Operations" (PEMDAS). When turned off, it behaves like a standard Japanese business calculator.

• Includes an RPN (Reverse Polish Notation) mode. This is a classic fixed-stack specification reminiscent of HP's 4-level RPN, with a customizable stack depth of 4 to 8 levels.

• Supports localized number formats (commas and periods) for various countries.


## Version history (last 5 releases)

### 1.2.11 — 2026-01-21

• Added a new keymap (Type 2) where the interval between every other row is exactly one octave. The traditional keymap (Type 1) can also be selected.
• The software libraries used in this app have been updated.

### 1.2.10 — 2024-08-07

• Spanish, French, German, Portuguese, and Italian are now supported.
• The software library used in this application has been updated.

### 1.2.9 — 2024-06-14

• The number format has been adjusted to match the system settings. You can now customize the decimal point and thousands separator characters to match the number formats of different countries.

• Some minor improvements have been made.

### 1.2.8 — 2024-05-27

• Added "No Sleep" option to not put the screen to sleep.

• The software library used in this application has been updated.

### 1.2.7 — 2024-05-10

You can now save your favorite background color and sound combination as "My Themes".

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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 2026-05-18.*