Gregorian Date to Julian Day Number Converter
Convert from Gregorian to Julian Day Number: enter a date below and see it as a Julian Day Number. The table further down lists the first day of every month of Gregorian year 2026 alongside the Julian Day Number.
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Gregorian months in 2026
The first day of every Gregorian month, with the Julian Day Number for the same day.
| Gregorian | Julian Day Number |
|---|---|
| 1 January 2026 | JDN 2461041.5 |
| 1 February 2026 | JDN 2461072.5 |
| 1 March 2026 | JDN 2461100.5 |
| 1 April 2026 | JDN 2461131.5 |
| 1 May 2026 | JDN 2461161.5 |
| 1 June 2026 | JDN 2461192.5 |
| 1 July 2026 | JDN 2461222.5 |
| 1 August 2026 | JDN 2461253.5 |
| 1 September 2026 | JDN 2461284.5 |
| 1 October 2026 | JDN 2461314.5 |
| 1 November 2026 | JDN 2461345.5 |
| 1 December 2026 | JDN 2461375.5 |
About these calendars
Gregorian
The Gregorian calendar is the most widely used civil calendar in the world. Introduced by Pope Gregory XIII in 1582 as a reform of the Julian calendar, it corrected the drift in the date of Easter by refining the leap year rule. It is a solar calendar with 365 days in a common year and 366 in a leap year.
Used in: Worldwide
Julian Day Number
The Julian Day Number is a continuous count of days since the beginning of the Julian Period on January 1, 4713 BCE (Julian calendar). It is used primarily in astronomy, chronology, and software to simplify date calculations across different calendar systems. Despite the name, it is unrelated to the Julian calendar.
Used in: International (astronomy, science)