How do I convert a Gregorian Calendar Date to a Julian Calendar Date?

[LibreGlow]

I would like to be able to know how to convert a “Gregorian Calendar Date” to a “Julian Calendar Date”, at least the Month and date. I’m aware there are about 3 different descriptions for “Julian Dates”, i.e. 5 and 7 digit numbers. What I seek, is if I enter December 25, the resulting Month and date will be January 7 (before the Gregorian year 2101, then it calculates to January 8). My interest is for the study of Holiday Observances, and I’m aware that the Julian Calendar Date (which uses the same months as the Gregorian) is currently 13 days behind the Gregorian Calendar Date, e.g. for the day of this posting,

Gregorian: 12/26 = Julian 12/13

One example is that many across the World still observe Christmas by the Julian Calendar Date, December 25, which currently results in January 7 (until 2100 A.D.) by the Gregorian Calendar Date.

Thanks,
Cliff

[ROSt53]

To the best of my knowledge LibO does not support the Julian Calendar but only the following calendars:

Thai Buddhist Calendar
Japanese Gengou Calendar
Gregorian Calendar
Korean Calendar
Arabic Islamic Calendar, currently supported for the following locales: ar_EG, ar_LB, ar_SA, and ar_TN
Jewish Calendar
Republic Of China Calendar

For conversion there are plenty of sites available in the internet.

[karolus]

For every Date between March of Year 1900 and March of Year 2100 you have to substract 13(days) -
the difference will increment 1 ( day ) for every year which can be divide by 100 but not by 400.

Karolus