Comparison

CITIZEN Eco vs AtomicClock

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

Head to head
About

CITIZEN Eco

This app connects your smartphone to compatible watches, allowing you to sync time, set alarms, and receive notifications for calls and messages. It also features world time settings and a light level indicator for the watch's power source.

Highlights
  • Automatic time synchronization
  • World time settings
  • Call and message notifications
  • Customizable alarms
  • Light level indicator
  • Smartphone search function
  • Link loss alerts
Features
Read full description

*Important Notice Thank you for using Citizen products. As of 12/31/2027, we will no longer provide service for dedicated apps for some models and functions used in conjunction with the apps. For details, see this link. https://www.citizenwatch-global.com/support/im/smartwatch.html Overview This is the official app for linking your smartphone with CITIZEN Bluetooth® watches. The app, which works with iPhone, enables you to set the time and the alarm for your watch, and to receive alerts for incoming calls, mails and texts. With the CITIZEN Bluetooth Watch, you get to enjoy an exquisite analogue watch that tells the accurate time wherever you are plus the great convenience of a smartphone link. CITIZEN Bluetooth features CITIZEN’s proprietary light-powered technology Eco-Drive. Eco-Drive eliminates the need to replace batteries or recharge via cable. Features 1. Time Sync Get the right time, all the time. When you connect with your smartphone, the time on your watch automatically updates to the current time (smartphone time). 2. World Time Get the time in any city around the world. Just touch the world map inside the app to set your watch to the locations time (world time). 3. Call Notification Find out when you get a call. The watch emits a sound or rotates the hands to let you know when you get a call. A filter function enables you to specify which callers will trigger alerts. 4. Message Notification Find out when you get a mail, text or SNS notification. The watch emits a sound or rotates the hands to let you know when a new e-mail or SNS notification has arrived. You can also select the apps for which you wish to receive notification alerts. 5. Alarm Set your alarm from your smartphone. You can set up to 3 alarms at one time. By setting your watch alarm using the smartphone app. The alarm can be set for different times and/or different days of the week. 6. Light Level Indicator See how much light—and power—your dial is getting. Find out how much power your watch is generating by tracking the light it’s exposed to on a daily, weekly or monthly basis. This unique function reflects CITIZEN’s status as a pioneer of light-powered technology. 7. Smartphone Search Find your smartphone easily. Misplaced your smartphone? Not a problem. Use your watch to locate your phone by having it emit a sound to indicate its whereabouts. (Range limitations apply.) 8. Link Loss Alert Get alerted when you’ve forgotten your smartphone somewhere. The watch emits a sound or rotates the hands to let you know when the link between your smartphone and your watch is broken. This app requires iOS 11.2 or later. Notifications have the options of 15 different original sounds, exclusively prepared for the W410 mode About Eco-Drive: Eco-Drive is a CITIZEN proprietary light-powered technology which eliminates the need for replacing batteries. Eco-Drive generates power from any kind of light—from sunlight to dim light—to drive the watch, and stores the surplus on a rechargeable cell. On a single full charge it can run for up to six months in total darkness*. For more details, click here. http://www.citizenwatch-global.com/technologies/index.html#eco-drive * Some models run for less than six months.

About

AtomicClock

This app displays the exact current time synchronized with NTP servers, offering a customizable clock view for precise time checks. It's ideal for setting watches, verifying timestamps, or comparing local and network time.

Highlights
  • Precise time from NTP servers
  • Customizable clock faces
  • Select or add time servers
  • Local and UTC views
  • 12/24 hour modes
  • Customizable time format
  • Acoustic ticking
Features
Read full description

Check precise NTP reference time at a glance. AtomicClock helps you set watches, wall clocks, cameras, and other devices, compare local time with UTC, and follow moments when every second matters. Clear analog and digital time AtomicClock displays current time from NTP servers that reference atomic clocks. Choose a predefined server or add your own, then view local or UTC time in a clean analog or digital clock. Customize your reference clock • Switch between 12-hour and 24-hour time • Customize the time format • Choose from multiple clock faces and hands • Use a smooth, fluid second hand • Add acoustic ticking or the Greenwich Time Signal • Tap the screen to hide information and controls, freeze the display, or mute ticking Details for precise time checks View technical NTP information, including round-trip time and server stratum. Whether you are checking a timestamp, preparing a camera, aligning a wall clock, or setting a watch by hand, the seconds remain clear and easy to follow. AtomicClock is free to use. AtomicClock Pro is available as a one-time purchase with no subscription. It unlocks your preferred clock face, hands, and font, removes ads, and includes upcoming Pro features. AtomicClock displays NTP reference time for comparison and does not change your device’s system time. Results can vary with the selected server, network conditions, and device behavior.

Screenshots

CITIZEN Eco4 screens
AtomicClock4 screens

Verdict

The call

The clearest difference is review sentiment: AtomicClock at 84% against CITIZEN Eco's 0%. AtomicClock also leads on update cadence (monthly vs every 5 months). CITIZEN Eco's advantage is in-app purchases (none vs 1) and ads (none vs shown). On price and device support 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. AtomicClock sells 1 one-off in-app purchase. CITIZEN Eco asks for nothing beyond the download.

UpkeepUpdate frequency

CITIZEN Eco ships an update every 5 months, AtomicClock monthly. The most recent releases landed on September 25, 2026 and October 29, 2026 respectively.

Scorecard6 real differences · 4 level
CITIZEN Eco versus AtomicClock: the parameters behind the verdict, then further details
ParameterCITIZEN EcoAtomicClock
PriceFreeFree
Rating—4.8 (5.6K ratings) — better
Positive reviews0.0% of reviews84.3% of reviews — better
Number of ratings—5.6K — better
Update frequencyEvery 5 monthsMonthly — better
AdsNo — betterYes
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPodiPhone, iPad
Requires iOS15.6 — better17.4
Further details — not scored
Size67 MB17 MB
Age rating4+4+
DeveloperCITIZEN WATCH CO.,LTDTimo Partl

Customer experience

CITIZEN Eco

Written reviews6 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

AtomicClock

All ratings5,568 ratings
Positive96.5%
Neutral1.7%
Negative1.8%
Written reviews242 reviews
Positive84.3%
Neutral3.3%
Negative12.4%

Bugs and requests

CITIZEN Eco

Not enough reviews yet to summarise bugs or requests.

AtomicClock

Reported bugs

3 issues
  • Crashes on certain iOS versions
  • Occasional freezing of hands
  • Countdown timer sound not working

Requested features

5 requests
  • Add GMT/dual time display
  • Implement widget support
  • Add different second hand sounds
  • Allow setting background color to match watch
  • Include alarm/timer functionality

In-app purchases

None

CITIZEN Eco

No in-app purchases

1 purchases

AtomicClock

One-time1
  • Lifetime Pro Version$6.99

Questions

Is CITIZEN Eco free?
CITIZEN Eco is free to download, with no in-app purchases.
Is AtomicClock free?
AtomicClock is free to download, with in-app purchases available.
Do CITIZEN Eco or AtomicClock have ads?
AtomicClock shows ads; CITIZEN Eco does not.
Which is updated more often, CITIZEN Eco or AtomicClock?
CITIZEN Eco ships an update every 5 months, and AtomicClock monthly. Most recently, CITIZEN Eco was updated on September 25, 2026 and AtomicClock on October 29, 2026.

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