Hebrew Date Converter

How the Hebrew calendar works

The Hebrew calendar is lunisolar: each month runs 29 or 30 days, tracking the cycle of the moon, while the year as a whole is kept in step with the solar seasons so that Passover always falls in spring and the fall holidays always land in autumn. A regular year has twelve months, from Tishrei through Elul, and runs about 353 to 355 days, a little shorter than the 365-day civil year. Because purely lunar months alone would drift roughly eleven days a year against the seasons, the calendar periodically inserts a whole extra month to catch back up. Within each month, the day itself is fixed by tradition rather than by direct observation of the moon today, following a calculated calendar established centuries ago. That correction, and the fixed 19-year pattern behind it, is covered in the Hebrew calendar explained.

Leap years: Adar I and Adar II

Seven years out of every fixed nineteen-year cycle are leap years (years 3, 6, 8, 11, 14, 17, and 19). In a leap year, an entire extra month is added before the regular month of Adar. The added month is called Adar I and the regular Adar becomes Adar II, giving the year thirteen months instead of twelve. Holidays and observances that normally fall in Adar, like Purim, move to Adar II in a leap year, since Adar II is treated as the "real" Adar. This nineteen-year pattern is what keeps the Hebrew calendar's twelve or thirteen lunar months aligned with the 365-day solar year over the long run, without ever needing an occasional single extra day the way the civil calendar uses leap years.

Why the date changes at sunset

A Hebrew day runs from evening to evening rather than from midnight to midnight, following the order used throughout the Torah's account of creation: "and there was evening, and there was morning." That means the Hebrew date already advances at sunset, hours before civil midnight. It's the reason Shabbat and every Jewish holiday begin the evening before their listed civil date, and it's why the converter above includes an "after sunset" option: a birth, a passing, or any other event that happened after dark on a given civil date actually falls on the following Hebrew day, not the one that matches the calendar date on a clock.

Common uses

People reach for a Hebrew date converter most often for three reasons. A bar or bat mitzvah date is set by finding the Hebrew birthday and locating the Shabbat nearest the day the child turns thirteen (or twelve, for a bat mitzvah in many communities). A yahrzeit is observed on the Hebrew date of a loved one's passing each year, which is why the after-sunset option above matters for getting it right the first time. And a Hebrew birthday itself, useful for anniversaries and life-cycle events, is simply the Hebrew date matching a Gregorian birth date, converted once and then tracked each year going forward. The converter above handles both directions from the same page, so you can move freely between "what's the Hebrew date for this civil day" and "what civil date does this Hebrew date land on this year." For the broader daily and yearly rhythm this calendar sets, see the Jewish calendar and the Daf Yomi calendar, or start a daily learning habit of your own.

Frequently asked questions