# Clockwork vs Atomic Sync

The clearest difference is in-app purchases: Atomic Sync at none against Clockwork's 1. Atomic Sync also leads on device support (3 vs 1). Clockwork's advantage is ads (none vs shown). On price, update cadence and iOS requirement there is nothing between them.

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

Clockwork ships an update every 3 weeks, Atomic Sync fortnightly. The most recent releases landed on September 11, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | Clockwork | Atomic Sync |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (24 ratings)](https://appshunter.io/ios/app/clockwork-watch-app/id1612061033/reviews)** | — |
| Number of ratings | **24** | — |
| Positive reviews | 42.9% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 3 weeks | **Fortnightly** |
| Monetization | Free with in-app purchases | — |
| Size | 242 MB | 27 MB |
| Requires iOS | 16.4 | **15.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Appfred AS](https://appshunter.io/developer/1612061035) | [Serhii Sereda](https://appshunter.io/developer/1887133214) |

## What reviewers say

### 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 |


### Atomic Sync

[App page](https://appshunter.io/ios/app/atomic-sync-radio-watch-time/id6761634713)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Clockwork free?

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

### Is Atomic Sync free?

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

### Do Clockwork or Atomic Sync have ads?

Atomic Sync shows ads; Clockwork does not.

### Which is updated more often, Clockwork or Atomic Sync?

Clockwork ships an update every 3 weeks, and Atomic Sync fortnightly. Most recently, Clockwork was updated on September 11, 2026 and Atomic Sync on September 19, 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.*