# Time Calibrator vs Clockwork

The clearest difference is rating: Clockwork at 4.4 against Time Calibrator's 2.7. Clockwork also leads on update cadence (every 3 weeks vs every 8 months) and ratings volume (24 vs 3). Time Calibrator's advantage is in-app purchases (none vs 1) and device support (3 vs 1). On price, ads and iOS requirement there is nothing between them.

Both are free to download. Clockwork sells 1 one-off in-app purchase. Time Calibrator asks for nothing beyond the download.

Clockwork holds the better App Store score, 4.4 against 2.7. That said, the two scores are not equally well evidenced: Clockwork has 24 ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 33% of Time Calibrator's written reviews are positive against 43% of Clockwork's.

Time Calibrator ships an update every 8 months, Clockwork every 3 weeks. The most recent releases landed on August 24, 2026 and September 11, 2026 respectively.

## The numbers

| Metric | Time Calibrator | Clockwork |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [2.7 (3 ratings)](https://appshunter.io/ios/app/time-calibrator/id786988278/reviews) | **[4.4 (24 ratings)](https://appshunter.io/ios/app/clockwork-watch-app/id1612061033/reviews)** |
| Number of ratings | 3 | **24** |
| Positive reviews | 33.3% of reviews | **42.9% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 8 months | **Every 3 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 8 MB | 242 MB |
| Requires iOS | **15.6** | 16.4 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Atomtime Suisse S.A.](https://appshunter.io/developer/786988281) | [Appfred AS](https://appshunter.io/developer/1612061035) |

## What reviewers say

### Time Calibrator

[App page](https://appshunter.io/ios/app/time-calibrator/id786988278)

This utility app provides precise local time and date information by connecting to an atomic clock server in Switzerland. It utilizes quantum technology to transmit this data at the speed of light directly to compatible i-Atomic watches.

**Highlights:** Accurate global time and date, Connects to Swiss atomic clock server, Quantum technology data transmission, Direct communication to i-Atomic watches, Light signal synchronization

**Features:** macOS Compatibility

**In-app purchases:** none


### Clockwork

[App page](https://appshunter.io/ios/app/clockwork-watch-app/id1612061033)

This app allows you to measure the accuracy of your watches using your phone's camera. It compares an image of your watch to an atomic clock to calculate its timekeeping offset. Track accuracy over time with graphs and store detailed watch information.

**Highlights:** Measure accuracy using images, Atomic clock synchronization, Accuracy over time graphs, Store detailed watch information, Dark mode support, Digital and analog atomic clock

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Clockwork Premium | $5.99 | one-time |


## Frequently asked questions

### Is Time Calibrator free?

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

### Is Clockwork free?

Clockwork is free to download, with in-app purchases available.

### Which has better reviews, Time Calibrator or Clockwork?

Clockwork is rated higher. Time Calibrator averages 2.7 out of 5 from 3 ratings, while Clockwork averages 4.4 from 24 ratings.

### Do Time Calibrator or Clockwork have ads?

Neither Time Calibrator nor Clockwork shows ads.

### Which is updated more often, Time Calibrator or Clockwork?

Time Calibrator ships an update every 8 months, and Clockwork every 3 weeks. Most recently, Time Calibrator was updated on August 24, 2026 and Clockwork on September 11, 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.*