UT1 Time Calculator
Calculate UT1 (Universal Time) based on Earth's rotation. UT1 is derived from astronomical observations and differs from UTC by up to 0.9 seconds.
Results
UTC
Mon, 18 May 2026 12:24:31 GMT
UT1
Mon, 18 May 2026 12:24:31 UT1
DUT1
0.0000s
Julian Date
2461179.017025
MJD
61178.517025
Julian Century
0.263765011
Earth Rotation Parameters
Greenwich Mean Sidereal Time (GMST)
04:09:20.00
62.333320 degrees
Earth Rotation Angle (ERA)
61.995349 degrees
1.082023 radians
About UT1
UT1 (Universal Time 1) is a time scale based on the rotation of the Earth. Unlike UTC (which is based on atomic clocks), UT1 is determined by observations of distant celestial objects. The difference between UT1 and UTC is called DUT1.
DUT1 = UT1 - UTC, and is kept within +/- 0.9 seconds by adding leap seconds to UTC. The International Earth Rotation and Reference Systems Service (IERS) publishes DUT1 values regularly.
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