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Atomic Clock Sync: a free configuration utility

While can help you look up accurate times around the world, our visitors have expressed much interest in our help to keep your local computer clock accurate, too. Atomic Clock Synchronization is the best way to make this happen.

Windows can do it ...

Windows has a built-in "service" that allows your computer to reference an atomic clock server, such as the atomic clock servers operated by the National Institute of Standards and Technology (NIST) in the United States. Your current computer time is compared with the current atomic time and an adjustment is made to keep your local computer up-to-date with the exact time now.

... but it is hard to configure

While it is great to have this functionality in Windows, configuring this time service is painful! If you want to sync more often than the default, you have to be very comfortable editing the System Registry OR you can use our Atomic Clock Sync program to do the work for you.

Use Atomic Clock Sync and go the easy route

Atomic Clock Sync offers an easy way to configure how often your computer will check in with an atomic clock server to keep your local system clock adjusted for accuracy. The default in Windows is to sync every 7 days, but you can easily change this to be more often if you find your computer clock gets behind or ahead too quickly.

Atomic Clock Sync can even help repair the Windows Time Service if your computer is no longer able to check for Internet Time updates as it normally would.

Best of all, you can download and use this utility at no cost to you!

Atomic Clock Sync includes no spyware! No ad banners! No cost! No questions asked! We give Atomic Clock Sync away for free simply to encourage you to use and return to World Time for the current times around the world. We appreciate your loyalty and we thank you for sharing our site with your friends, too! Atomic Clock Sync helps keep your local clock accurate and WorldTimeServer has the accurate clocks for everywhere else!

Download Atomic Clock Sync

This download is signed for your safety by our company. If you have User Access Control turned on, you should see a prompt listing the Verified Publisher as being Chaos Software Group, Inc., so if you see something else, or the download is not signed, please make certain you are downloading the file direct from our web site!

download  download Atomic Clock Sync 3.5 (891 KB)
[supports Windows 8, Windows 7, Vista, Server 2003, XP or 2000]
[Version 3.5 is now compatible with both 64-bit and 32-bit Windows!]

IMPORTANT NOTE: You must have the correct time zone selected on your computer AND have the correct daylight saving time rules in place in your operating system in order to have the Internet Time synchronize process work properly. If the dates for Daylight Saving Time (DST) changed recently in your area, you must update your operating system with the new rules. Microsoft releases patches when necessary for newer versions of Windows, but with older versions, you may have to update the registry yourself or find a third-party tool to do it.

About Atomic Clock Sync

This utility is provided free of charge, so please feel free to share it, redistribute it, and use it any way you wish, provided you do not alter the program in any way.

Version 3.5 requires Windows 8, Windows 7, Vista, Windows Server 2003, Windows XP, or Windows 2000. It is an executable file that does not require installation. Just run it whenever you want to review and or reconfigure your Atomic Clock Sync settings in Windows or when you need to repair the Windows Time Service in Windows.

Version 3.5 was initially released on September 13, 2012.

Old Versions - Downloads and Revision History

If you are using Windows Me, 98, 95 or NT 4, you can still download the old release by clicking here.


More Information keeps track of local daylight saving time rules all over the world. We use this information to offer accurate current times for anywhere you need.

You can view our complete list of countries around the world to see all the locations we cover.

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