AtomicClock: Exact NTP Time

Contains adsIn-app purchases
18.5K reviews
Content rating
Everyone
500K+
Downloads
Content rating
Everyone
Digital Purchases
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About this app

Need the exact time to set a watch, align a wall clock, compare UTC, or catch a moment where seconds matter? AtomicClock shows precise reference time from NTP time servers in a clear analog or digital clock.

NTP servers provide network time referenced to atomic clocks. Choose a predefined or custom time server, then view local time or a UTC clock in 12-hour or 24-hour format. Use AtomicClock as an NTP clock, precision clock, reference clock, or seconds clock for manual time checks.

Practical ways to use AtomicClock

• Set a watch, wall clock, camera, or other device manually
• Compare local time with UTC
• Check precise time before an event or scheduled task
• Keep a clear clock visible while you work using picture-in-picture with Pro

Clock display and signal options

• Analog clock and digital clock views
• Custom time formats, clock faces, hands, and fonts
• Smooth, fluid second-hand movement
• Optional acoustic ticking sounds
• Greenwich Time Signal
• Home screen clock widget with time and date
• Tap actions to hide information, freeze the display, or mute ticking

For technical NTP checks, view details such as the selected time server, round-trip time, and stratum. Accuracy depends on the server, network conditions, and device behavior.

AtomicClock is designed for reference time and manual clock sync. It does not automatically change device system time. The home screen widget uses system time for technical and battery reasons.

AtomicClock is free to use. AtomicClock Pro adds preferred clock styles and fonts, many widget customization options, all tap actions, picture-in-picture, and ad removal. Pro is a one-time purchase through your Google Play account with no subscription.
Precise atomic time — UTC clock, Greenwich Time Signal and clock widget
Updated on
Aug 6, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • This app may share these data types with third parties
    Location, App activity and 2 others
  • This app may collect these data types
    Location, App activity and 2 others
  • Data is encrypted in transit
  • Data can’t be deleted

Ratings and reviews

17.1K reviews
Gary Pascoe
May 5, 2021
I liked the app a lot. I've been using it for a couple of years now. There is a great deal of satasfaction in keeping reliably accurate precise time. This makes it easy. A great tool for synchronizing every thing not already auto synced to a standard. My car, my watch, the oven and microwaves. The list goes on. This has become my go to reference source because I like its design.
16 people found this review helpful
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Timo Partl
June 4, 2019
If you have the app running permanently on the screen it will have higher battery consumption than a static page. The reason for this is the milliseconds display which updates every 40ms which triggers a relayout of the view - this is how Android works. Turning the milliseconds off in the app settings and switching to the dark theme should help
Lisa Stone
June 18, 2026
This app has become very beneficial for me. I can set the clock on my phone screen that I can see plainly and clearly. With visual impairments it is sometimes difficult for me to see smaller things, especially from a distance. It is also beneficial for me to keep track of time when I'm focused on a project, to be able to have the clock right there on my ohone screen.
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Ezra b
July 1, 2026
After the last upgrade, I can't get the widget to have white font and a black background. Something changed. I want the wigets backgroud to be black, and the font white like it was before the upgrade. After the upgrade the backgroud turned white and the font black, i tryed to use the settings of the wiget with no success after upgrade number 2, fixed thank you, much success!
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Timo Partl
July 1, 2026
Glad this is fixed now. Thanks for the updated review. Enjoy the app!

What’s new

• Redesigned the color picker for app and widget colors, with presets, a color wheel, and brightness control
• Pro: widget backgrounds can now be customized with color and opacity, and default widget colors follow your Android theme better
• Settings now use clearer icons to make customization options easier to scan
• Custom NTP servers now support host:port entries and better validation before saving