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-May-23-Sat 17:40:35 LT 2461184.23651620 2461184 Local Time Zone TZ +00:00:00 TZ +0.00000000 Universal Time UTC 2026-May-23-Sat 17:40:35 UTC 2461184.23651620 2461184 Delta T Correction +00:01:09 DT +0.00080075 Terrestrial Time TT 2026-May-23-Sat 17:41:44 TT 2461184.23731696 2461184 TAI Correction -00:00:32.184 -0.00037250 Atomic Time TAI 2026-May-23-Sat 17:41:12 TAI 2461184.23694446 2461184 Astronomical JD TT 2461184.23731696 Horizons Delta T +69.185082 sec ============================================================================= ======================================== JD NUMBER TABLE Year:2026 | Month:May Gregorian Calendar Calendar Date JD Number Julian Date Year-Mmm-Dn-DoW JD at 12h JD at 00h ---------------- --------- ----------- 2026-May-01-Fri 2461162 2461161.5 2026-May-02-Sat 2461163 2461162.5 2026-May-03-Sun 2461164 2461163.5 2026-May-04-Mon 2461165 2461164.5 2026-May-05-Tue 2461166 2461165.5 2026-May-06-Wed 2461167 2461166.5 2026-May-07-Thu 2461168 2461167.5 2026-May-08-Fri 2461169 2461168.5 2026-May-09-Sat 2461170 2461169.5 2026-May-10-Sun 2461171 2461170.5 2026-May-11-Mon 2461172 2461171.5 2026-May-12-Tue 2461173 2461172.5 2026-May-13-Wed 2461174 2461173.5 2026-May-14-Thu 2461175 2461174.5 2026-May-15-Fri 2461176 2461175.5 2026-May-16-Sat 2461177 2461176.5 2026-May-17-Sun 2461178 2461177.5 2026-May-18-Mon 2461179 2461178.5 2026-May-19-Tue 2461180 2461179.5 2026-May-20-Wed 2461181 2461180.5 2026-May-21-Thu 2461182 2461181.5 2026-May-22-Fri 2461183 2461182.5 2026-May-23-Sat 2461184 2461183.5 2026-May-24-Sun 2461185 2461184.5 2026-May-25-Mon 2461186 2461185.5 2026-May-26-Tue 2461187 2461186.5 2026-May-27-Wed 2461188 2461187.5 2026-May-28-Thu 2461189 2461188.5 2026-May-29-Fri 2461190 2461189.5 2026-May-30-Sat 2461191 2461190.5 2026-May-31-Sun 2461192 2461191.5 ---------------- --------- ----------- 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