Julian Date and Julian Day Number Calculator Valid Over The Period From 1600 to 2200 on the Gregorian Calendar
Local Calendar Date   Year      Month    Day	Local Clock Time 00:00  to  24:00	Local Time Zone Offset From UT Negative | Positive  =  West | East UTC
Julian Date ============================================================================= Calendar Date Time Julian Date JD Num =============== ============ ================ ======= Local Date/Time LT 2025-Dec-15-Mon 05:17:52 LT 2461024.72074074 2461025 Local Time Zone TZ +00:00:00 TZ +0.00000000 Universal Time UTC 2025-Dec-15-Mon 05:17:52 UTC 2461024.72074074 2461025 Delta T Correction +00:01:09 DT +0.00080073 Terrestrial Time TT 2025-Dec-15-Mon 05:19:01 TT 2461024.72154148 2461025 TAI Correction -00:00:32.184 -0.00037250 Atomic Time TAI 2025-Dec-15-Mon 05:18:29 TAI 2461024.72116897 2461025 Astronomical JD TT 2461024.72154148 Horizons Delta T +69.183449 sec ============================================================================= ======================================== JD NUMBER TABLE Year:2025 | Month:Dec Gregorian Calendar Calendar Date JD Number Julian Date Year-Mmm-Dn-DoW JD at 12h JD at 00h ---------------- --------- ----------- 2025-Dec-01-Mon 2461011 2461010.5 2025-Dec-02-Tue 2461012 2461011.5 2025-Dec-03-Wed 2461013 2461012.5 2025-Dec-04-Thu 2461014 2461013.5 2025-Dec-05-Fri 2461015 2461014.5 2025-Dec-06-Sat 2461016 2461015.5 2025-Dec-07-Sun 2461017 2461016.5 2025-Dec-08-Mon 2461018 2461017.5 2025-Dec-09-Tue 2461019 2461018.5 2025-Dec-10-Wed 2461020 2461019.5 2025-Dec-11-Thu 2461021 2461020.5 2025-Dec-12-Fri 2461022 2461021.5 2025-Dec-13-Sat 2461023 2461022.5 2025-Dec-14-Sun 2461024 2461023.5 2025-Dec-15-Mon 2461025 2461024.5 2025-Dec-16-Tue 2461026 2461025.5 2025-Dec-17-Wed 2461027 2461026.5 2025-Dec-18-Thu 2461028 2461027.5 2025-Dec-19-Fri 2461029 2461028.5 2025-Dec-20-Sat 2461030 2461029.5 2025-Dec-21-Sun 2461031 2461030.5 2025-Dec-22-Mon 2461032 2461031.5 2025-Dec-23-Tue 2461033 2461032.5 2025-Dec-24-Wed 2461034 2461033.5 2025-Dec-25-Thu 2461035 2461034.5 2025-Dec-26-Fri 2461036 2461035.5 2025-Dec-27-Sat 2461037 2461036.5 2025-Dec-28-Sun 2461038 2461037.5 2025-Dec-29-Mon 2461039 2461038.5 2025-Dec-30-Tue 2461040 2461039.5 2025-Dec-31-Wed 2461041 2461040.5 ---------------- --------- ----------- Year-Mmm-Dn-DoW JD Number Julian Date Calendar Date JD at 12h JD at 00h ========================================
SYMBOLS, TIME SCALES AND RELATIONSHIPS LT = Local (Clock) Time TZ = Local Standard Time Zone Offset From UT (Negative|Positive = West|East) NOTE: When Daylight Saving or Summer Time is in effect, then the time zone offset is one hour less than under standard time. For example, the standard time zone offset for New York City, USA, is −5 hours when standard time is in effect but when Daylight Saving Time is in effect, the time zone offset from UT is −4 hours instead. Universal Time is always standard time. UT = Universal Time Scale = UT1 From 1600 to 1961 = UTC From 1962 onward = LT − (TZ) DT = Horizons Delta T (Could be negative or positive, depending on date.) = TT − UT TT = Terrestrial Time Scale (Used for formal astronomical computations.) = UT + (DT) = LT − (TZ) + (DT) TAI = International Atomic Time Scale = TT − 00:00:32.184 = LT - (TZ) + (DT) − 00:00:32.184 JD = Julian Date (a floating point decimal value). Contains both the complete calendar date and time of day information where the decimal fraction part indicates the time of day. JD Number = Julian Day Number (always an integer value). = Unique sequential serial number of the date on the calendar. It contains only the calendar date information. = floor(JD + 0.5) DoW = Day of Week index (0=Sun, 1=Mon, 2=Tue, 3=Wed, 4=Thu, 5=Fri, 6=Sat) = (floor(JD + 0.5) + 1) mod 7 = (JDNumber + 1) mod 7
Download This PHP 7 Program: 598 kb - Julian Date and JD Number Calculator
Program by Jay Tanner Revised: Thursday, January 01, 1970 at 12:00:00 AM UTC