What is Today's Julian Date?

This is a free online tool to convert Gregorian Date to Julian Date.

Julian dates (JD) are a count of days that began at noon Universal Time on January 1, 4713 BC. Julian dates are commonly used by astronomers as a standardised form of timekeeping. JD is also used by food manufacturers on occasion, though their dates are calculated differently. For those of us who are used to the Gregorian calendar, JD are a little difficult to understand, so there are a few tricks to reading them. Because JD are written in different ways depending on the context, make sure you're using the method that corresponds to the type of JD you're working with.

Today's Date is [yyyy-mm-dd]
Today's Julian Date is [yyddd]

Julian Date is most commonly referred to as yyddd date format (yy=year and ddd=day). In mainframe and other circles, this is the common term for a date. A Julian date, on the other hand, can mean a variety of things. A Julian date is defined by astronomers as the number of days since the start of the Julian Period (January 1, 4713 BC). The Smithsonian Astrophysical Observatory developed the 'Modified Julian Date' to record the Sputnik satellite's orbit in 18 bits.

A yyddd (or similar format such as yyyyddd, yy-ddd) date is more correctly called an ordinal date. However in the mainframe world, we call them 'Julian Dates', and so we've used this term on this page.

Julian Date Converter

Julian Date Calendar 2021


Do you need a reference for every day of the year? Check out the calendar below for Julian Date references on every day of the year.

Day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1001032060091121152182213244274305335
2002033061092122153183214245275306336
3003034062093123154184215246276307337
4004035063094124155185216247277308338
5005036064095125156186217248278309339
6006037065096126157187218249279310340
7007038066097127158188219250280311341
8008039067098128159189220251281312342
9009040068099129160190221252282313343
10010041069100130161191222253283314344
11011042070101131162192223254284315345
12012043071102132163193224255285316346
13013044072103133164194225256286317347
14014045073104134165195226257287318348
15015046074105135166196227258288319349
16016047075106136167197228259289320350
17017048076107137168198229260290321351
18018049077108138169199230261291322352
19019050078109139170200231262292323353
20020051079110140171201232263293324354
21021052080111141172202233264294325355
22022053081112142173203234265295326356
23023054082113143174204235266296327357
24024055083114144175205236267297328358
25025056084115145176206237268298329359
26026057085116146177207238269299330360
27027058086117147178208239270300331361
28028059087118148179209240271301332362
29029 088119149180210241272302333363
30030 089120150181211242273303334364
31031 090 151 212243 304 365

Julian Date Calendar Leap Year


Day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1001032061092122153183214245275306336
2002033062093123154184215246276307337
3003034063094124155185216247277308338
4004035064095125156186217248278309339
5005036065096126157187218249279310340
6006037066097127158188219250280311341
7007038067098128159189220251281312342
8008039068099129160190221252282313343
9009040069100130161191222253283314344
10010041070101131162192223254284315345
11011042071102132163193224255285316346
12012043072103133164194225256286317347
13013044073104134165195226257287318348
14014045074105135166196227258288319349
15015046075106136167197228259289320350
16016047076107137168198229260290321351
17017048077108138169199230261291322352
18018049078109139170200231262292323353
19019050079110140171201232263293324354
20020051080111141172202233264294325355
21021052081112142173203234265295326356
22022053082113143174204235266296327357
23023054083114144175205236267297328358
24024055084115145176206237268298329359
25025056085116146177207238269299330360
26026057086117147178208239270300 331361
27027058087118148179209240271301332362
28028059088119149180210241272302333363
29029060089120150181211242273303334364
30030 090121151182212243274304335365
31031 091 152 213244 305 366