Jewish Birthday Calculator
Enter your Gregorian birth date to find your Hebrew birth date and your upcoming Jewish birthdays.
Note: For Adar birthdays in leap years, this tool uses a practical matching rule (Adar I/Adar II mapped to Adar in non-leap years).
What this Jewish calendar birthday calculator does
A Jewish birthday is based on the Hebrew calendar, not the Gregorian calendar. That means your Hebrew birthday may fall on a different civil date each year. This calculator helps you:
- Convert your Gregorian birth date to a Hebrew birth date.
- Find your next Jewish birthday from any reference date.
- See your upcoming five Jewish birthdays in Gregorian dates.
- Estimate your Hebrew age on your next birthday.
How the calculator works
1) Convert birth date to Hebrew date
The tool converts your birth date into the Hebrew calendar and captures the Hebrew day and month. Those two values are what define your recurring Jewish birthday.
2) Search forward for matching Hebrew dates
Starting from your “as of” date, the calculator checks each day until it finds a date where the Hebrew day and month match your birth Hebrew day and month.
3) Handle leap-year month differences
Hebrew leap years include an extra month (Adar I and Adar II). Because birthday customs can vary by community and halachic opinion, this calculator uses a straightforward computational convention:
- Born in Adar I → matches Adar I in leap years, Adar in non-leap years.
- Born in Adar II → matches Adar II in leap years, Adar in non-leap years.
- Born in Adar (non-leap) → matched to Adar or Adar II where applicable.
Why people use a Jewish birthday calculator
People use this for synagogue honors, yahrzeit planning, family records, lifecycle events, and simply to know when to celebrate according to the Hebrew calendar. It is also useful for planning reminders in digital calendars.
Important note
This is a practical date calculator, not a rabbinic ruling. For halachic decisions (for example, bar/bat mitzvah timing, observance edge cases, or regional/custom disputes), consult a qualified rabbi.
Quick FAQ
Why is my Jewish birthday different every year on the civil calendar?
The Hebrew and Gregorian calendars have different month structures and leap systems, so dates shift year to year.
Can I use this for future planning?
Yes. Set the “Calculate As Of” date to any day, and the tool will return upcoming birthdays from that point.
Does this work on mobile?
Yes. The calculator and layout are responsive and work on modern mobile browsers.