Mean Solar Time Calculator
Calculate Local Mean Solar Time (LMST) and Greenwich Mean Solar Time (GMST). Mean solar time uses a fictitious mean sun that moves uniformly along the celestial equator.
Mean Solar Time
UTC / GMST
18:38:49.00
Greenwich Mean Solar Time
LMST
18:38:49.00
Local Mean Solar Time
Civil Time
18:38:49.00
Standard Time Zone (UTC+0)
LMST - Civil
0.00 min
Difference from zone time
Time Parameters
Standard Meridian
0 deg
Longitude Time Offset
0.0000 hours
Solar/Sidereal Ratio
1.00273791
Day Length Comparison
Mean Solar Day
24:00:00.000
86,400 SI seconds (by definition)
Sidereal Day
23:56:04.091
Rotation relative to stars
Difference
3:55.909
Solar day is longer
About Mean Solar Time
Mean Solar Time is based on a fictitious "mean sun" that moves uniformly along the celestial equator at a constant rate. Unlike apparent solar time (sundial time), mean solar time does not vary throughout the year. The difference between mean and apparent solar time is the Equation of Time. Modern civil time is based on mean solar time, with UTC serving as the global reference.