# Atomic Clock PRO vs Atomic Sync

The clearest difference is in-app purchases: Atomic Sync at none against Atomic Clock PRO's 2. Atomic Sync also leads on update cadence (fortnightly vs every 3 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Atomic Clock PRO sells 2 in-app purchases, starting at $1.99 per month. Atomic Sync asks for nothing beyond the download.

Atomic Clock PRO ships an update every 3 months, Atomic Sync fortnightly. The most recent releases landed on September 26, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | Atomic Clock PRO | Atomic Sync |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (10K ratings)](https://appshunter.io/ios/app/atomic-clock-pro/id899090224/reviews)** | — |
| Number of ratings | **10K** | — |
| Positive reviews | 72.7% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | Yes |
| Update frequency | Every 3 months | **Fortnightly** |
| Monetization | Free with in-app purchases | — |
| Size | 6 MB | 27 MB |
| Requires iOS | 15.6 | **15.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Brachmann Online Marketing GmbH & Co. KG](https://appshunter.io/developer/682848918) | [Serhii Sereda](https://appshunter.io/developer/1887133214) |

## What reviewers say

### Atomic Clock PRO

[App page](https://appshunter.io/ios/app/atomic-clock-pro/id899090224)

Get the most accurate time from an official atomic clock server. This app automatically detects your time zone and allows custom backgrounds. Easily switch between digital and analog clock displays with a swipe.

**Highlights:** Exact time from atomic clock, Automatic time zone recognition, Customizable background images, Digital and analog clock modes, Optional sound alerts, Color customization

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $1.99 | per month |
| Remove Ads | $5.99 | one-time |

**What reviewers like**

- ⭐ Accurate time display
- 📟 Useful for timing events
- 🕰️ Helpful for setting other clocks
- 🔍 Large, easy-to-read clock face

**What reviewers complain about**

- 💸 Subscription model for ad-free version
- 📢 Excessive advertisements
- 🔍 Small font for seconds display
- 🔀 Difficulty in displaying both analog and digital clocks simultaneously

**Reported bugs**

- Second hand occasionally runs in reverse
- Digital clock display cuts off on some devices
- Inconsistent behavior when switching between clock types

**Requested features**

- Customizable clock face options
- Ability to set widget on home screen
- Sync with system clock to automatically update 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 Atomic Clock PRO free?

Atomic Clock PRO 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 Atomic Clock PRO or Atomic Sync have ads?

Both Atomic Clock PRO and Atomic Sync show ads.

### Which is updated more often, Atomic Clock PRO or Atomic Sync?

Atomic Clock PRO ships an update every 3 months, and Atomic Sync fortnightly. Most recently, Atomic Clock PRO was updated on September 26, 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.*