Comparison

Clockwork vs Atomic Sync

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

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
Read full description

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

About

Atomic Sync

Synchronize your radio-controlled watch using your phone's speaker to emulate atomic time signals. Supports various international time signals and offers smart reminders for regular synchronization. Works offline and prioritizes user privacy.

Highlights
  • Emulates atomic time signals
  • Supports multiple international time signals
  • Offline synchronization
  • Smart reminders for syncing
  • User-friendly design with dark/light themes
  • Privacy-focused with no data collection
Features
Read full description

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

Clockwork4 screens
Atomic Sync3 screens

Verdict

The call

The clearest difference is rating: Clockwork at 4.4 against Atomic Sync's 2.5. Clockwork also leads on ads (none vs shown) and ratings volume (24 vs 2). Atomic Sync's advantage is in-app purchases (none vs 1) and device support (3 vs 1). On price, update cadence, monetization model 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

CostPrice · In-app purchases · Ads · Monetization

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

ReceptionRating · Positive reviews · Number of ratings

Clockwork holds the better App Store score, 4.4 against 2.5. That said, the two scores are not equally well evidenced: Clockwork has 24 ratings behind it against 2, so its average is the more settled of the two.

UpkeepUpdate frequency

Clockwork ships an update every 3 weeks, Atomic Sync fortnightly. The most recent releases landed on November 3, 2026 and October 31, 2026 respectively.

Scorecard5 real differences · 5 level
Clockwork versus Atomic Sync: the parameters behind the verdict, then further details
ParameterClockworkAtomic Sync
PriceFreeFree
Rating4.4 (24 ratings) — better2.5 (2 ratings)
Positive reviews45.5% of reviews—
Number of ratings24 — better2
Update frequencyEvery 3 weeksFortnightly — better
AdsNo — betterYes
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS16.415.0 — better
Further details — not scored
Size242 MB27 MB
Age rating4+4+
DeveloperAppfred ASSerhii Sereda

In-app purchases

1 purchases

Clockwork

One-time1
  • Clockwork Premium$5.99
None

Atomic Sync

No in-app purchases

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.
Which has better reviews, Clockwork or Atomic Sync?
Clockwork is rated higher. Clockwork averages 4.4 out of 5 from 24 ratings, while Atomic Sync averages 2.5 from 2 ratings.
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 November 3, 2026 and Atomic Sync on October 31, 2026.

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