I did compare just a few dates and they agreed with a site I checked them on,
but it revealed a "flaw" in the process. This site,
http://www.hebcal.com/converter/ , brought that to my attention.

The formula assumes that you're asking about a date before sundown on that
date.

That is, if you use the Gregorian date of 5 AUG 2009, the formula returns Av
15 5769. That is correct UNTIL sundown on 05 Aug 2009. After sunset the
correct answer is Av 16 5769.

"Joe Golden" wrote:

I have an excel table of dates of death that I need to convert to Hebrew
calendar preferably in a single column formula which then can be exported to
Word for letters to relatives each year for yahrzeit reminders..