Does anyone know of a method to make converting Jewish calendar dates to Gregorian calendar dates easy?
Also, is there a program or website that does this?
I use http://Hebcal.com for this.
N.B. I did some programming for them.
There is an algorithm that they use, but it's not simple enough to do by hand.
Emacs provides the functions of a desk calendar, with a diary of planned or past events.
p h Display Hebrew date for selected day (calendar-print-hebrew-date).
github-misc/Hebrew Calendar/code/cal-hebrew.el has the code used in 1209 lines of lisp.
You can see a summary article at Hebrew Dating which points to Calendrical Calculations: The Millennium Edition,
Edward M. Reingold and Nachum
Dershowitz, Cambridge: Cambridge University Press, 2001. which gives the algorithms and calculations. There are also one page universal conversion sheets such as in
Calendrical Tabulations, 1900-2200, Edward M. Reingold and Nachum Dershowitz, Cambridge: Cambridge University Press, 2002. This book (see Fig. 1) gives a set of fully accurate, easy-to-use tabl es that simultaneously display the date on different calendars over a 300-year period.
Safari shows the lisp code used at Appendix B Lisp Implementation by Edward M. Reingold, Nachum Dershowitz