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This public service is cooperatively provided by the two time agencies of the United States: a Department of Commerce agency, the National Institute of Standards and Technology (NIST), and the U. S. Naval Observatory (USNO). Readings from the clocks of these agencies contribute to world time, called Coordinated Universal Time (UTC). The time maintained by both agencies should never differ by more than 0.000 0001 seconds from UTC (see recent comparisons).
Go to: Time & Frequency Division, NIST Time Service Department, USNO
This web site is intended as a time-of-day service only. It should not be used to measure frequency or time interval, nor should it be used to establish traceability to NIST or the USNO.

To see the animated clock, be sure that java is enabled on your browser. In most cases, a new download of java will fix the animated clock. Otherwise, you can try a different browser.  Also, you may be behind a firewall and you will need to have your network administrator open port 8013 in order for it to work.

Also, you can click on "Disable Java Animation" in order to see a static clock.

If the light/dark region looks incorrect, a click of reload *should* fix it. Otherwise there may be a problem in your browser with using javascript.

To convert 24-hour time to 12 hour time, subtract 12 if the time is greater than 12.
A toggle switch for this will be featured in future versions of the site.

For questions about a.m./p.m., noon/midnight and UTC, check our FAQ

For sunrise/sunset information contact Astronomical Applications Web Page

Setting Your Computer Clock
  You can download software from NIST and USNO in order to use the Internet to automatically set your computer clock to the correct time.
Time Zones
For a more detailed time zone map, look at our map of US time zones.
For time zone offsets around the world, please consult our world time zone map.
Please send any comments or questions to: timeinfo@boulder.nist.gov
However, due to the volume of email we receive, we cannot always respond to each one individually.

Disclaimer: Linking to an external site does not imply recommendation or endorsement of the information or commercial products by NIST or USNO.

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