Information on the Jewish/Civil Calendar

This program accepts years of the Jewish calendar, separated by a space, for example:
5780 5781
and produces on the screen a calendar of that year with a visually equivalent civil calendar opposite it for easy conversion of dates. Click on the box marked YEAR(S) to commence, then enter the years. You may enter any number of years before pressing return or enter, although you may want to limit the number initially to five or so, to avoid confusion. When the list appears, you may scroll up and down with your mouse.

The months of the civil year are abbreviated to


and of the Jewish calendar to


Each Jewish month has its name on the left. The corresponding secular dates will have the name of the month on the right, and when the secular month changes it will be indicated on the right also.

You may enter a civil year in the form -70 for BCE dates and +70 for CE dates. The Jewish year beginning prior to Jan 1 of that year will be displayed. If you wish to complete the desired civil year, you may enter the next civil year on the line, preceded by a space. You may mix Jewish and civil years.

You may enter CE or AD instead of + or BC or BCE instead of the minus sign if you wish. In this case, enter 1987CE, for example, with no space between the numeral and the letters. If you use the Opera browser, you must use this form.
This program has been tested and works equally well on the Safari, Explorer, Chrome, and Firefox browsers.

The year 0 is not meaningful in either calendar. No date prior to 1 in the Jewish calendar should be entered. The program will calculate any future year instantly for many years ahead.

A status line appears at intervals, indicating the civil and Jewish years for the preceding section, and the number of days in each. Jewish years may contain 354, 355, 356, 384, 385 or 386 days according to circumstances.

All civil dates are according to the Gregorian Calendar which first came into use in 1582 and was accepted in different places at different times. For example, it was accepted in England in 1752, and in Russia only after the Bolshevik Revolution in 1917. Prior to that date the Julian calendar was in use. At the present time the Julian calendar is 13 days behind the Gregorian Calendar, so that March 15 1917 in our reckoning is March 2 in the Julian calendar. The following table shows the number of days that must be subtracted from the Gregorian date given here to find the Julian date. In the centuries before the current era the civil calendar was intercalated erratically, so a simple subtraction is not possible. Note that the change in the number to subtract applies from March 1 in the century year, since in the Julian Calendar that will be February 29 except in years divisible by 400 which are leap years in the Gregorian calendar also.

Gregorian > Julian. Days to subtract.
Century # To Subtract Century # To Subtract
21 13 11 6
20 13 10 5
19 12 9 4
18 11 8 4
17 10 7 3
16 10 6 2
15 9 5 1
14 8 4 1
13 7 3 0
12 7 2 -1
1 -2

I originally wrote this program in the Icon programming language for the UNIVAC 1100 timesharing computer, and ported it to the World Wide Web in 1992.

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Alan D. Corré