# GNSS Time Calculator

**GPS Time** is the number of seconds since January 6, 1980, 00:00:00

**GAL Time** (Galileo Time) is the number of seconds since August 22, 1999, 00:00:00

**UNIX Time** is the number of seconds since January 1, 1970, 00:00:00

**Julian Date** is the number of days since January 1, 4713 B.C., 12:00:00; defines the number of mean solar days elapsed since the epoch January 1.5d, 4713 before Christ.[Hoffman-Wellenhof]

**MJD** (Modified Julian Date) is the number of days since January 1, 4713 B.C., 00:00:00, removing the first two digits. MJD=JD-24000000.5

**MJD2000** (Modified Julian Date 2000) is the number of days since January 1, 2000, 00:00:00

*Important note:* No leap seconds are considered in the computations except for TAI and TT

Leap seconds to be updated December 2023