Comparison

Codex Calc vs Hierarchical To

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

Head to head
About

Codex Calc

This app offers a powerful yet intuitive calculator experience with a variety of modes including scientific, unit conversion, and tip calculation. It features a customizable interface and a detailed history tape for all your calculations.

Highlights
  • Full scientific calculator functions
  • Unit converter
  • Tip calculator
  • RPN mode
  • History tape
  • Customizable interface
  • Multiple visual themes
Features
Read full description

Codex Calc is the calculator for the rest of us: easy and intuitive, without sacrificing power and capabilities. Calculator • Unit Converter • Tip Calculator • RPN Mode • Full Scientific • History Tape All the power you need, wrapped in a beautifully designed interface that's simple without being simplistic. ADAPTS TO YOU Do you like big buttons, or small? Like minimalist interfaces, or are you a fan of bright and flashy? Prefer small fonts to see more detail, or big text and easy to read buttons? Codex Calc adapts itself to the way *you* like to work. FEATURES Everything you'd expect, plus: • History tape records all entries and calculations • Full suite of standard and scientific calculator functions • Unit conversion mode for forward and reverse conversions • Full tip calculator mode - taxes, tip, per-person amounts • RPN mode fully integrated • Rotation lock and sound on/off toggles • Seven different professionally designed visual themes • Multi-number memory and full set of memory-store operators • Full control over history tape font size • Single and multiple-line history tape formats • Large and small button sizes • Settings for customization (number formatting, behavior of clear key, display of calculation details, much more) Calculations: • Trig functions in degrees and radians • Log and power/exponentials • Scientific notation / exponent mode • Rounding and truncating • Random number generation • Parenthesis and sub-expressions ...and more! INTUITIVE TOUCH INTERFACE Take full advantage of your device's capabilities: • Overlays - rather than making buttons smaller to fit more, Codex Calc uses intuitive overlays on the existing buttons. • Popup Menus - hidden until you need them, pop-up context menus give you more power when the default action isn't quite what you need. • Zoomable History Tape - Tap the history tape to expand for more detail, change the font size, copy contents to clipboard, or forward as an email. View as single-lines to save space, or use multi-line view for more detail. • Multiple Flexible Layouts - Portrait and landscape, large and small buttons, and seven different graphical themes. • Easy-Touch Everything - Codex Calc's entire design approach revolves around "touch to activate." Tap the tape to see it bigger, swipe to scroll, long-press a button for more options, tap the display to copy or paste, etc.

About

Hierarchical To

Organize complex projects with infinitely layered tasks. View all parent, child, and grandchild tasks at a glance without multiple taps. Collapse or expand task branches for clarity and utilize repeat functions for recurring to-dos.

Highlights
  • Infinite task layering
  • Collapse/expand task branches
  • View all task levels at once
  • Today's To-do List
  • Task repeat function
  • Task move and copy
  • Completion history
Features
Read full description

Do you want to layer tasks? For example, there are various types of cleaning such as floor cleaning, kitchen areas, bathrooms, and balconies. Furthermore, kitchen areas can be divided into sinks, stoves, ventilation fans, drains, etc. It is hard to see task list if it is not layered, and you can not distinguish between the drainage ditch in the kitchen and the drainage ditch in the bathroom. The "Hierarchical To-do list" can be useful in such cases. As the name suggests, the "Hierarchical task list" allows you to layer tasks, and there are no restrictions on the hierarchy. * Since the width of the screen is limited, there are display restrictions. You can display up to about 12 levels on the vertical screen. You can see all parent tasks, child tasks, and grandchild tasks at a glance as shown in the screenshot. You don't have to tap multiple times to confirm even if the hierarchy is deep. If you don't want to see the child tasks, you can collapse them by tapping the ▽ button of the parent task. To display the child task again, tap the ▶ button. + "Today's To-do List" and "To-do List" This app has "Today's To-do List" and "To-do List". "To-do List" is a list that has all tasks other than "Today's to-do list". In the "ToDo list", tasks are divided into groups and you can collapse them by tapping the group. Both lists can be reordered, so you can sort them in order of priority or what to do today. In addition, by using the task repeat function, task move, and copy functions described later, you can easily create a "to-do list" without having to enter the task to be repeated each time. ■ Task repeat By adding repeat settings such as daily / weekly / monthly / yearly to the tasks in the "ToDo list", the task will be automatically copied to the "Today's to-do list" when the specified date comes. You can also adjust the interval such as every 10 days or every 2 months and start date of repeat settings. Also, if you specify a deadline, it will be automatically moved to the "Today's To-do list" when the deadline is reached. By using this function that tasks are automatically added to the "Today's To-do List", You don't have to remember regular tasks and the task deadline. Once you have registered your repeat settings, you don't have to worry about them until they are added to your "Today's To-do List". ■ Operation method ・Completion of task You can complete (delete) a task by tapping the check box. You can check the completed tasks in "Completion history". If you tap it by mistake, tap the "Cancel" button. ・Right slide of task You can move and copy a task between the "To Do List" and the "To Do List" by sliding the task to the right. If the same thing is in the destination list, overwrite it. ・Left slide of task You can see the Move, Edit, and Delete buttons by sliding a task to the left. You can move the task to the beginning / end of the list by pressing the "Move" button displayed at this time. Press "Edit" to display the edit screen where you can edit the deadline, repeat settings, subtasks, etc. You can also display the edit screen by double tapping the task. ・Sorting tasks Please long-press the check box to reorder a task. ・Edit bar When editing a task directly, you can do the following in the edit bar above the keyboard: - You can change the hierarchy of the task being edited with "←" and "→". - The two buttons to the right of "←" and "→" allow you to add new tasks above and below the task you are editing. - Press the "x" button to close the keyboard. ・Folding all groups function Tappping the icon to the left of the search button in To-Do List can fold all groups. Tapping it when all groups folded can unfold all groups. If you have any requests, please feel free to contact us by email, Twitter, or reviews. ■ Contact ・Email mizuki.naotaka@gmail.com ・Twitter https://twitter.com/NaotakaMizuki

Screenshots

Codex Calc4 screens
Hierarchical To4 screens

Verdict

The call

The clearest difference is price: Hierarchical To at Free against Codex Calc's $0.99. Hierarchical To also leads on rating (5.0 vs 4.0) and update cadence (every 2 months vs every 6 months). Codex Calc's advantage is in-app purchases (none vs 1) and ads (none vs shown). On review sentiment, ratings volume, device support and iOS requirement 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

Hierarchical To is free to download; Codex Calc costs $0.99 up front. Hierarchical To sells 1 one-off in-app purchase. Codex Calc asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Hierarchical To holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 1 and 1 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

UpkeepUpdate frequency

Codex Calc ships an update every 6 months, Hierarchical To every 2 months. The most recent releases landed on June 5, 2026 and June 10, 2026 respectively.

Scorecard6 real differences · 4 level
Codex Calc versus Hierarchical To: the parameters behind the verdict, then further details
ParameterCodex CalcHierarchical To
Price$0.99Free — better
Rating4.0 (1 ratings)5.0 (1 ratings) — better
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings11
Update frequencyEvery 6 monthsEvery 2 months — better
AdsNo — betterYes
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS12.012.0
Further details — not scored
Size11 MB51 MB
Age rating4+4+
DeveloperDriftwood Studio Software LLCYuuki Shimizu

Customer experience

Codex Calc

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Hierarchical To

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews5 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Codex Calc

No in-app purchases

1 purchases

Hierarchical To

One-time1
  • Remove ads$2.99

Questions

Is Codex Calc free?
Codex Calc costs $0.99, with no in-app purchases.
Is Hierarchical To free?
Hierarchical To is free to download, with in-app purchases available.
Which has better reviews, Codex Calc or Hierarchical To?
Hierarchical To is rated higher. Codex Calc averages 4.0 out of 5 from 1 ratings, while Hierarchical To averages 5.0 from 1 ratings.
Do Codex Calc or Hierarchical To have ads?
Hierarchical To shows ads; Codex Calc does not.
Which is updated more often, Codex Calc or Hierarchical To?
Codex Calc ships an update every 6 months, and Hierarchical To every 2 months. Most recently, Codex Calc was updated on June 5, 2026 and Hierarchical To on June 10, 2026.

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