The Julian Day or Julian Date (JD) is a continuous count of days and fractions since January 1, 4713 BC 12:00:00 UTC (noon), according to the Julian calendar.
It is used primarily by astronomers and scientists to avoid issues with calendar systems and time zones. The Julian calendar was proposed in 46 BC by Julius Caesar and was used in Europe until the Gregorian calendar reform in 1582, which is the calendar system we use today.
This page shows the current Julian Day and provides converters between:
- JD - Julian Date
- MJD - Modified Julian Day (starts in 1858)
- JDN - Julian Day Number (integer day number)
Convert a Julian Date (JD) to a human-readable date
The (full) Julian Date includes the fractional day, so the time of day is represented as a decimal fraction of the day.
The current Julian Date is
Convert Modified Julian Date (MJD) to a readable date
In the Modified Julian Date (or Day) system, the epoch is on November 17, 1858 00:00:00 UTC.
To calculate between JD and MJD use the formula: MJD = JD - 2400000.5
The current Modified Julian Date is