Official U.S. time now in every time zone
The current official time across the United States, accurate to a fraction of a second, like the government clock at time.gov.
Time.gov is the U.S. government's official time website, run by NIST (National Institute of Standards and Technology) with the U.S. Naval Observatory. The clocks on this page show the same official time: they're corrected against internet time servers that are synced to atomic clocks. onlineclock.app is an independent site, not affiliated with NIST or the Naval Observatory.
How the United States keeps official time
Two agencies share the job. NIST, in Boulder, Colorado, maintains the national time scale for civilian use with an ensemble of atomic clocks, including the NIST-F cesium fountain clocks. The U.S. Naval Observatory in Washington, D.C. keeps the master clock for the military and GPS. Their time scales are kept within a few billionths of a second of each other and contribute to Coordinated Universal Time (UTC), the world's time standard.
NIST shares that time in several ways: the time.gov website, internet time servers that computers and phones use to set their clocks, and radio station WWVB near Fort Collins, Colorado, whose 60 kHz signal sets "atomic" wall clocks and watches across most of North America.
Why your clock may be off
Phones and most computers set themselves from internet time servers, so they're usually right to within a second. A computer with automatic time sync turned off, a cable box or a microwave can drift by minutes. The line above the clocks shows how far this device is from internet time right now. For a single big clock, use the exact time or the atomic clock page.
Questions people ask
Is this the same time as time.gov?
Yes, to within a fraction of a second. Time.gov shows the official U.S. time kept by NIST and the U.S. Naval Observatory. This page shows the same time: it reads your device clock and corrects it against internet time servers that are themselves synced to atomic clocks.
Who runs time.gov?
Time.gov is a public service of the National Institute of Standards and Technology (NIST), part of the U.S. Department of Commerce, together with the U.S. Naval Observatory (USNO), which keeps official time for the Department of Defense. This page is not affiliated with either.
Where does official U.S. time come from?
From ensembles of atomic clocks at NIST in Boulder, Colorado, and at the U.S. Naval Observatory in Washington, D.C. NIST also broadcasts the time by radio from station WWVB near Fort Collins, Colorado, which is what sets "atomic" wall clocks and watches.
How accurate is my computer clock?
Usually within a second if it syncs automatically, but it can drift by seconds or minutes if syncing is off. The line under the clocks above shows how far your device is from internet time right now. See how we get the time.
How many time zones does the United States have?
Nine standard time zones are set by law: Atlantic, Eastern, Central, Mountain, Pacific, Alaska, Hawaii-Aleutian, Samoa and Chamorro. The 50 states use six of them.
Related: US time zones map · exact time · atomic clock · UTC time now · how we get the time
Last updated October 23, 2026.