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-Jun-03-Tue 17:10:45 LT 2460830.21579861 2460830 Local Time Zone TZ +00:00:00 TZ +0.00000000 Universal Time UTC 2025-Jun-03-Tue 17:10:45 UTC 2460830.21579861 2460830 Delta T Correction +00:01:09 DT +0.00080075 Terrestrial Time TT 2025-Jun-03-Tue 17:11:54 TT 2460830.21659936 2460830 TAI Correction -00:00:32.184 -0.00037250 Atomic Time TAI 2025-Jun-03-Tue 17:11:22 TAI 2460830.21622686 2460830 Astronomical JD TT 2460830.21659936 Horizons Delta T +69.184840 sec ============================================================================= ======================================== JD NUMBER TABLE Year:2025 | Month:Jun Gregorian Calendar Calendar Date JD Number Julian Date Year-Mmm-Dn-DoW JD at 12h JD at 00h ---------------- --------- ----------- 2025-Jun-01-Sun 2460828 2460827.5 2025-Jun-02-Mon 2460829 2460828.5 2025-Jun-03-Tue 2460830 2460829.5 2025-Jun-04-Wed 2460831 2460830.5 2025-Jun-05-Thu 2460832 2460831.5 2025-Jun-06-Fri 2460833 2460832.5 2025-Jun-07-Sat 2460834 2460833.5 2025-Jun-08-Sun 2460835 2460834.5 2025-Jun-09-Mon 2460836 2460835.5 2025-Jun-10-Tue 2460837 2460836.5 2025-Jun-11-Wed 2460838 2460837.5 2025-Jun-12-Thu 2460839 2460838.5 2025-Jun-13-Fri 2460840 2460839.5 2025-Jun-14-Sat 2460841 2460840.5 2025-Jun-15-Sun 2460842 2460841.5 2025-Jun-16-Mon 2460843 2460842.5 2025-Jun-17-Tue 2460844 2460843.5 2025-Jun-18-Wed 2460845 2460844.5 2025-Jun-19-Thu 2460846 2460845.5 2025-Jun-20-Fri 2460847 2460846.5 2025-Jun-21-Sat 2460848 2460847.5 2025-Jun-22-Sun 2460849 2460848.5 2025-Jun-23-Mon 2460850 2460849.5 2025-Jun-24-Tue 2460851 2460850.5 2025-Jun-25-Wed 2460852 2460851.5 2025-Jun-26-Thu 2460853 2460852.5 2025-Jun-27-Fri 2460854 2460853.5 2025-Jun-28-Sat 2460855 2460854.5 2025-Jun-29-Sun 2460856 2460855.5 2025-Jun-30-Mon 2460857 2460856.5 ---------------- --------- ----------- 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