# Calendar Clock vs ThetaCalc

The clearest difference is review sentiment: ThetaCalc at 100% against Calendar Clock's 0%. ThetaCalc also leads on price (Free vs $0.99) and update cadence (every 3 months vs every 41 months). On ads, in-app purchases and device support there is nothing between them.

ThetaCalc is free to download; Calendar Clock costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Calendar Clock ships an update every 41 months, ThetaCalc every 3 months. The most recent releases landed on October 24, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Calendar Clock | ThetaCalc |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Rating | — | **[4.3 (4 ratings)](https://appshunter.io/ios/app/thetacalc/id1521614636/reviews)** |
| Number of ratings | — | **4** |
| Positive reviews | 0.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 41 months | **Every 3 months** |
| Monetization | Paid | **Free** |
| Size | 4 MB | 1 MB |
| Requires iOS | 26.5 | **17.6** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Systemiko Inc.](https://appshunter.io/developer/680630947) | [Felix Stehli](https://appshunter.io/developer/1521614638) |

## What reviewers say

### Calendar Clock

[App page](https://appshunter.io/ios/app/calendar-clock/id1451445740)

This app displays the current year, month, week, and time on a single screen with a clean design. It offers customizable theme colors and functions as a desk clock. The app disables device sleep mode while active.

**Highlights:** All-in-one screen display, Year, month, week, day, hour, minute, second, Switchable theme colors (dark, light, green, blue), Disables device sleep mode, Acts as a desk clock

**Features:** macOS Compatibility

**In-app purchases:** none


### ThetaCalc

[App page](https://appshunter.io/ios/app/thetacalc/id1521614636)

This utility app provides a Reverse Polish Notation (RPN) calculator. Users can extend its functionality by programming custom functions and equations using JavaScript.

**Highlights:** Reverse Polish Notation (RPN) calculator, User-programmable functions, JavaScript equation support, Extensible functionality

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Calendar Clock free?

Calendar Clock costs $0.99, with no in-app purchases.

### Is ThetaCalc free?

ThetaCalc is free to download, with no in-app purchases.

### Do Calendar Clock or ThetaCalc have ads?

Neither Calendar Clock nor ThetaCalc shows ads.

### Which is updated more often, Calendar Clock or ThetaCalc?

Calendar Clock ships an update every 41 months, and ThetaCalc every 3 months. Most recently, Calendar Clock was updated on October 24, 2026 and ThetaCalc on October 1, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*