An interesting program to convert Jewish-calendar dates into the widely used Gregorian or Western calendar

http://stevemorse.org/hebrewcalendar/hebrewcalendar.htm Jewish Calendar Demystified

Appears the author is a Y/E Jewish creationist *
Six Thousand versus Fifteen Billion

Those of us who have studied science have been taught that the universe was created in the Big Bang some fifteen billion years ago. But the story of creation says that everything started not quite six thousand years ago. Now that’s quite a discrepancy – a difference of fourteen billion, nine hundred ninety-nine million, nine hundred ninety-four thousand years. Or, to put it another way, a 2.5 million percent error. How can this be?

One popular explanation has to do with the actual time taken for creation—those six circled days in the calendar above. It was six days, to be sure, but how long were those days? They were the periods between the start of one darkness and the start of the next darkness. Was that 24 hours, the time from sunset to sunset? How could it be since the sun wasn’t created until the fourth day? So they might have been very long periods of time and in total added up to fifteen billion years. A far-fetched theory, and possibly an after-the-fact rationalization, but it does bring the biblical and scientific theories into compliance.

However there’s an explanation that I like even better. When Adam and Eve were created, they were not infants crawling around on the ground. They were full-grown adults, or so the story in Genesis implies. So why should we think that the rocks and mountains and fossils were pristine? They too could have been aged at the time they were created to give all appearances of having been around for billions of years. In other words, there was an initial condition to this freshly created universe that made it look like it was billions of years old. We got a used universe! Perhaps even a recycled one that the creator had lying around from some previous experiments. It certainly brings everything into perspective.
* Except for the recycled used universe idea in the last sentence above!