Comparison

Calc vs O'der stack

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Calc

This app offers a high-precision scientific calculator with over 50 digits of accuracy. It supports advanced mathematical functions, complex arithmetic, and programmable features for derivatives, integrals, and root finding.

Highlights
  • High-precision calculations (50+ digits)
  • Extensive mathematical functions
  • Programmable features
  • Complex arithmetic
  • Graphing capabilities
  • Derivative and integral calculation
Features
Read full description

Calc-50 is a high-precision scientific graphing RPN calculator. It carries over 50 digits of accuracy and has a large number of mathematical functions, including trig and hyperbolic functions and their inverses, and math special functions such as gamma, beta, psi, exponential integral, sine, cosine, and log integrals, Bessel functions, and more. It is programmable, with functions that take user functions and find derivatives, integrals, function max/min, and roots. Calc-50 also provides complex arithmetic and elementary functions.

About

O'der stack

Features
Read full description

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. —Functions— 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 https://ictfractal.github.io/official/PrivacyPolicy.html Terms of service https://ictfractal.github.io/official/AppTerms.pdf Disclaimer 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.

Screenshots

Calc1 screens
O'der stack4 screens

Verdict

The call

The clearest difference is in-app purchases: Calc at none against O'der stack's 3. Calc also leads on iOS requirement (12.0 vs 15.6). O'der stack's advantage is update cadence (every 3 months vs every 10 months). On price, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. O'der stack sells 3 one-off in-app purchases. Calc asks for nothing beyond the download.

UpkeepUpdate frequency

Calc ships an update every 10 months, O'der stack every 3 months. The most recent releases landed on October 2, 2026 and October 1, 2026 respectively.

Scorecard3 real differences · 7 level
Calc versus O'der stack: the parameters behind the verdict, then further details
ParameterCalcO'der stack
PriceFreeFree
Rating3.0 (2 ratings) — better—
Positive reviews50.0% of reviews—
Number of ratings2 — better—
Update frequencyEvery 10 monthsEvery 3 months — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS12.0 — better15.6
Further details — not scored
Size38 MB59 MB
Age rating4+4+
DeveloperDavid SmithICT Fractal Inc.

In-app purchases

None

Calc

No in-app purchases

3 purchases

O'der stack

One-time3
  • Free trial for 7 days.Free
  • Activate for 1 month.$0.99
  • Activate for year.$9.99

Questions

Is Calc free?
Calc is free to download, with no in-app purchases.
Is O'der stack free?
O'der stack is free to download, with in-app purchases available.
Do Calc or O'der stack have ads?
Neither Calc nor O'der stack shows ads.
Which is updated more often, Calc or O'der stack?
Calc ships an update every 10 months, and O'der stack every 3 months. Most recently, Calc was updated on October 2, 2026 and O'der stack on October 1, 2026.

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