O'der stack is a scientific calculator that is precise for up to 38 digits and is highly flexible.

It can be used for various purposes, from learning to professional use, and has many functions that are convenient when mastered.

The formulas described can be saved together with the results of the calculations and easily shared among members.

Also, labels and memos can be set for formulas as well as each item that makes up the formulas.
For example, by adding the label "radius" to "50" in 2 x 50 x π, it is possible to make the meaning of the formula even clearer.
It is also perfect for entering explanations of formulas as memos and using them as tools to assist in learning.

O'der stack offers two plans, the Pro plan which offers unlimited use of all functions, as well as the Free plan which makes it usable as an easy-to-use scientific calculator.

1. A powerful editing function that allows partial overwriting of values without erasing the formula
2. Label and memo functions to support the understanding of formulas
3. A clipboard function that allows formulas to be pasted in notebooks, etc.
4. Setting the precision of calculations from 0 digits to 38 digits
5. Setting units (degrees/radians) for trigonometric functions
6. Setting the format of displaying results of calculations (normal notation, scientific notation, and percentage notation)
7. Basic functions (exponentiation and nth root)
8. Undo function

—Pro plan—
Please download O'der stack and try out the Pro plan for free for seven days.
In addition to all the functions in the Free plan, the Pro plan allows for the activation of even more convenient functions.

1. Functions to save and load formulas and calculation histories
2. Function to share formulas and calculation histories
3. A sub-formula function that allows for the breakdown into several formulas and simple entry
4. 18 types of versatile and widely-used functions
5. 652 highly precise numerical and physical constants and observed values
6. Setting the format of displaying results of calculations (binary, octal, hexadecimal)
       - Each item can be selected from 8bit, 16bit, 24bit, 32bit, 64bit and 128bit.
       - Supports negative values and decimal points.
       - Negative values are displayed in complement.

After the free trial has ended, if you would like to continue to use the Pro plan, a purchase of a non-autorenew-subscriptionis required.
For a subscription, you can choose either a monthly purchase or yearly purchase, and the yearly purchase allows you to enjoy a discount worth two months of monthly purchases.

Payment will be charged to your Apple ID account at the confirmation of purchase.
If you purchase a plan during the effective period, it will be extended by the number of days of the purchased plan from the end date.
The plan is effective on all devices linked to the purchased Apple ID account.

Privacy policy

Terms of service

ICT Fractal Inc. does not guarantee the accuracy, credibility, and compatibility of the results of calculations and information provided through this app.
Furthermore, it does not bear the responsibility for direct or indirect damages that might occur through this app.

What’s New

Version 2.2

Bug fix.


Activate for 1 month.
Activate all features for 1 month.
Rp 15ribu
Activate for year.
Activate all features for 1 year.
Rp 149ribu

In-App Purchases

Free trial for 7 days.
Activate all features for 7 days.
Rp 0


ICT Fractal Inc.
70.7 MB

Requires iOS 12.1 or later. Compatible with iPhone, iPad and iPod touch.


English, Japanese

Age Rating
In-App Purchases
  1. Free trial for 7 days.
  2. Activate for 1 month. Rp 15ribu
  3. Activate for year. Rp 149ribu


  • Family Sharing

    Up to six family members will be able to use this app with Family Sharing enabled.

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