Hebrew date tools
Three calculators built on the same tested Hebrew calendar arithmetic.
- Hebrew birthday
Your Hebrew birth date, your next Hebrew birthdays, and a Hebrew-to-Gregorian converter.
- Yahrzeit
The Hebrew date of a death and the coming yahrzeit dates, with the evening each one begins.
- Bar / Bat Mitzvah
The date at 13 or 12, the Shabbat on or after it, and that Shabbat’s Torah portion.
How the Hebrew calendar works
The Hebrew calendar is lunisolar. Months follow the moon (29 or 30 days), and a thirteenth month, Adar I, is added in 7 years of every 19 so that Pesach stays in spring. Two months, Cheshvan and Kislev, change length from year to year so that Rosh Hashana does not fall on certain weekdays. As a result a Hebrew year has between 353 and 385 days, and a Hebrew date moves around the Gregorian calendar by up to a month.
A Hebrew day runs from nightfall to nightfall. Someone born on a Tuesday evening after sunset was born, by the Hebrew calendar, on Wednesday’s date. Tick the after-sunset box in that case. If the time was close to sunset, check the local sunset time for that date, or ask your rabbi.
Our conversions use the fixed arithmetic of the Hebrew calendar as set out in Reingold and Dershowitz, Calendrical Calculations, and are tested against the open-source Hebcal library for every day from 1800 to 2239.