Clockwork vs Atomic Sync
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Clockwork
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.
- Measure accuracy using images
- Atomic clock synchronization
- Accuracy over time graphs
- Store detailed watch information
- Dark mode support
- Digital and analog atomic clock
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Measure the accuracy of your watches today! Clockwork includes several useful features. You can store watch information, measure watch accuracy, and set your watch using a clock synchronized with atomic time. Check it out now! _MEASUREMENTS USING IMAGES_ Most other watch measurement apps require either third-party equipment or that you press a button at a specific time. Additional equipment is often expensive, and timing a button press is difficult to do precisely. Clockwork solves this by letting you take a picture of your watch and indicate the time shown in the image. We then synchronize the image capture time with atomic time before comparing it with the time shown on the watch to calculate an offset. Taking measurements over time provides a real-world view of your watch's accuracy. _GRAPHS_ Watch your measurements over time on a beautifully crafted graph. The graph shows how your watch's accuracy changes over time and offers several modes to help you understand its performance. _WHY MEASURE?_ Knowing the accuracy of your watch is interesting on its own, but it also has several practical uses. It can indicate when it is time for a service, and documented accuracy could increase resale value, especially for vintage watches. _STORE DETAILED INFORMATION_ In case of theft or accidents, it will always help to have your information stored in a secure place. _ATOMIC CLOCK, DARK MODE AND MUCH MORE!_ Clockwork includes an atomic clock in both digital and analog formats to help you set your watch as precisely as possible. Powerful settings such as Dark or Light mode, separate day and date formats, and different ways to sort your watches let you customize the app to your liking. // Appfred AS © 2026
Atomic Sync
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Sync Your Radio-Controlled Watch in Minutes! Atomic Sync emulates official atomic time signals to synchronize your radio-controlled watch — no tower reception needed. Works with Casio G-Shock, Citizen, Lacrosse, Junghans, Braun and other atomic watches. SUPPORTED TIME SIGNALS: • WWVB (60 kHz) — United States • DCF77 (77.5 kHz) — Germany / Europe • JJY40 / JJY60 (40/60 kHz) — Japan • MSF (60 kHz) — United Kingdom • BPC (68.5 kHz) — China • RBU (66.66 kHz) — Russia HOW IT WORKS: 1. Select your region or time signal 2. Place your phone near your watch (see visual guide) 3. Tap Start and wait 1-10 minutes 4. Your watch syncs to atomic time — done! BEAST MODE (Premium Sync): Need faster sync? Watch a short rewarded video to activate Beast Mode — our enhanced signal algorithm for quicker, more reliable synchronization. Unlimited use, no subscriptions. SMART REMINDERS: Set local notifications to remind you to sync your watch daily, weekly, bi-weekly, monthly or custom. Never lose atomic precision again. OFFLINE & ACCURATE: • All signals generated locally — no internet required for sync • Optional NTP time source sync for maximum accuracy when online • Last known time cached for offline use USER-FRIENDLY DESIGN: • Dark/Light theme (auto-switch) • Universal positioning guide with animated signal waves • Simple 4-step flow, no brand selection needed • 16 languages supported PRIVACY FIRST: • No location access required • No personal data collected • No account registration needed COMPATIBLE WITH: Casio G-Shock, Pro Trek, Edifice • Citizen Eco-Drive • Lacrosse Technology • Junghans Mega • Braun watches • And any watch supporting WWVB/DCF77/JJY/MSF/BPC signals. TIPS FOR SUCCESS: • Use maximum phone volume during sync • Keep phone and watch still, 2-10 cm apart • Avoid metal surfaces and electronic interference DISCLAIMER: Atomic Sync is a third-party tool and is not affiliated with, endorsed by, or connected to Casio, Citizen, or any watch manufacturer. Time signal emulation is for personal use only. Success depends on watch model, environment, and device hardware.
Screenshots
Verdict
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.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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.
| Parameter | Clockwork | Atomic Sync |
|---|---|---|
| Price | Free | Free |
| Rating | 4.4 (24 ratings) — better | — |
| Positive reviews | 42.9% of reviews | — |
| Number of ratings | 24 — better | — |
| Update frequency | Every 3 weeks | Fortnightly — better |
| Ads | No — better | Yes |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone | iPhone, iPad, iPod — better |
| Requires iOS | 16.4 | 15.0 — better |
| Further details — not scored | ||
| Size | 242 MB | 27 MB |
| Age rating | 4+ | 4+ |
| Developer | Appfred AS | Serhii Sereda |
In-app purchases
Clockwork
- Clockwork Premium$5.99
Atomic Sync
No in-app purchases









