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Julian Date Converter

Convert a calendar date to a Julian date (YYDDD or YYYYDDD, as used on military records and food lot codes) and back, get the astronomical Julian Day Number, and look up any day of the year in the table.

Updated November 4, 2026. Free, no sign-up; everything runs in your browser and nothing you type is stored.

Julian date converter

Calendar date

Julian date (YYDDD)

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–YYYYDDD

–Day of year (DDD)

–Astronomical Julian Day Number

–Julian Date at 00:00 UTC

–Days left in the year

Julian date to calendar date (YYDDD, YYYYDDD or DDD)Year (for 3-digit DDD)

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Julian day calculator: day-of-year table

Year

Which "Julian date" do you need?

The term is used for two different numbers:

Ordinal date (YYDDD): the 2-digit year plus the day of the year from 001 to 365 (366 in leap years). November 4, 2026 is day 308, so 26308. It's used by the US military, on food and drug lot codes and expiration stamps, by FDA and USDA date coding, in mainframe and manufacturing systems, and in some government records. The 4-digit form is 2026308.
Astronomical Julian Day Number (JDN): a continuous count of days since noon UTC on January 1, 4713 BC (Julian calendar), used in astronomy and software date math. November 4, 2026 is JDN 2,461,349 (the day that begins at noon UTC).

How to calculate Julian date numbers by hand

Add the days in each earlier month to the day of the month. For November 4, 2026: Jan 31 + Feb 28 + Mar 31 + Apr 30 + May 31 + Jun 30 + Jul 31 + Aug 31 + Sep 30 + Oct 31 = 304, + 4 = 308. In a leap year (2028, 2032), add 1 for any date after February 28. Use the table above to look up any day at a glance.

The Julian calendar (Julius Caesar's, still used by some Orthodox churches) is something else again: it currently runs 13 days behind the Gregorian calendar.

Common questions

What is today's Julian date?

November 4, 2026 is 26308 (day 308 of 2026).

How do I read a Julian date code on food?

The first digit or two is the year and the next three are the day of the year. 26308 = day 308 of 2026 = November 4, 2026.

How do I calculate a Julian date?

Add the days of all previous months to the day of the month, and put the 2-digit year in front.

What is the Julian day number?

The astronomical count of days since January 1, 4713 BC; November 4, 2026 is 2,461,349.

How many days are in 2026?

365. 2028 is the next leap year with 366.

Sources

General information, not financial, tax or legal advice. Check important numbers with the official source before acting on them.