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 2026-Apr-04-Sat 17:56:57 LT 2461135.24788194 2461135 Local Time Zone TZ +00:00:00 TZ +0.00000000 Universal Time UTC 2026-Apr-04-Sat 17:56:57 UTC 2461135.24788194 2461135 Delta T Correction +00:01:09 DT +0.00080076 Terrestrial Time TT 2026-Apr-04-Sat 17:58:06 TT 2461135.24868270 2461135 TAI Correction -00:00:32.184 -0.00037250 Atomic Time TAI 2026-Apr-04-Sat 17:57:34 TAI 2461135.24831020 2461135 Astronomical JD TT 2461135.24868270 Horizons Delta T +69.185634 sec ============================================================================= ======================================== JD NUMBER TABLE Year:2026 | Month:Apr Gregorian Calendar Calendar Date JD Number Julian Date Year-Mmm-Dn-DoW JD at 12h JD at 00h ---------------- --------- ----------- 2026-Apr-01-Wed 2461132 2461131.5 2026-Apr-02-Thu 2461133 2461132.5 2026-Apr-03-Fri 2461134 2461133.5 2026-Apr-04-Sat 2461135 2461134.5 2026-Apr-05-Sun 2461136 2461135.5 2026-Apr-06-Mon 2461137 2461136.5 2026-Apr-07-Tue 2461138 2461137.5 2026-Apr-08-Wed 2461139 2461138.5 2026-Apr-09-Thu 2461140 2461139.5 2026-Apr-10-Fri 2461141 2461140.5 2026-Apr-11-Sat 2461142 2461141.5 2026-Apr-12-Sun 2461143 2461142.5 2026-Apr-13-Mon 2461144 2461143.5 2026-Apr-14-Tue 2461145 2461144.5 2026-Apr-15-Wed 2461146 2461145.5 2026-Apr-16-Thu 2461147 2461146.5 2026-Apr-17-Fri 2461148 2461147.5 2026-Apr-18-Sat 2461149 2461148.5 2026-Apr-19-Sun 2461150 2461149.5 2026-Apr-20-Mon 2461151 2461150.5 2026-Apr-21-Tue 2461152 2461151.5 2026-Apr-22-Wed 2461153 2461152.5 2026-Apr-23-Thu 2461154 2461153.5 2026-Apr-24-Fri 2461155 2461154.5 2026-Apr-25-Sat 2461156 2461155.5 2026-Apr-26-Sun 2461157 2461156.5 2026-Apr-27-Mon 2461158 2461157.5 2026-Apr-28-Tue 2461159 2461158.5 2026-Apr-29-Wed 2461160 2461159.5 2026-Apr-30-Thu 2461161 2461160.5 ---------------- --------- ----------- 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