What Is the Jewish Calendar and How Do You Use It?

Updated

The Jewish calendar (also called the Hebrew calendar) is a lunisolar calendar: months follow the moon, while years are kept in step with the sun by adding a leap month seven times in a 19-year cycle. That's why Hebrew dates drift against the Gregorian calendar from year to year but always land in the same season — Passover is always in spring. To use it practically, you need three things: a way to convert a Hebrew date to a Gregorian one (or back), a source for holiday and Shabbat times, and a way to carry those dates into the calendar app you already use. Hebcal.com provides all three, including holiday calendars, a Hebrew–Gregorian date converter, candle-lighting and Havdalah times for over 100,000 cities, Torah readings, and Yahrzeit reminders.

How the Hebrew calendar counts months and years

A Hebrew year has 12 or 13 months. In a leap year, the month of Adar is doubled (Adar I and Adar II) so that the lunar year catches up with the solar year. Because of this, the same Hebrew date falls on a different Gregorian date each year — the gap can be a few weeks.

Hebrew days also start at sunset, not midnight. That's why Shabbat and holidays begin on the evening before the date listed on a Gregorian calendar.

A concrete example from Hebcal's own homepage: Sunday, 11 October 2026 corresponds to 30th of Tishrei, 5787, which is Rosh Chodesh Cheshvan (the start of the new month of Cheshvan) and the week of Parashat Noach.

What the calendar tracks

Hebcal organizes observances into several categories, each useful for a different purpose:

Category What it includes Typical use
Major holidays The main festivals Scheduling time off, planning travel
Minor & modern holidays Lesser observances and modern Israeli holidays Cultural and educational reference
Rosh Chodesh Start of each Hebrew month Monthly marking
Minor fasts Fast days Observance planning
Special Shabbatot Named Shabbatot with special readings Synagogue scheduling
Shabbat times Candle-lighting and Havdalah Weekly planning
Torah readings Aliyah-by-aliyah breakdown, full kriyah, triennial cycle, weekday readings Leyning coordination
Daily learning Daf Yomi, Mishna Yomi Study schedules

Converting between Hebrew and Gregorian dates

Use the date converter when you need to know what a Hebrew date is in Gregorian terms, or the reverse — for example, to find the Gregorian date of a yahrzeit or to check what Hebrew date a birthday falls on.

  1. Open the date converter on Hebcal.
  2. Enter the date you know — either a Hebrew date (day, month, year) or a Gregorian date.
  3. Read the corresponding date in the other system. The converter also shows today's date in a Hebrew font.

The expected result is a one-to-one mapping, so you can confirm you've entered the right year before relying on it for an observance.

Finding Shabbat candle-lighting and Havdalah times

Candle-lighting and Havdalah times depend on your location, since they're tied to local sunset.

  1. Go to the Shabbat Times section.
  2. Enter your city. Hebcal supports over 100,000 world cities.
  3. Get start and end times for Shabbat, holidays, and fast days, plus a year-at-a-glance view.

If your city isn't listed directly, choose the nearest supported location and adjust — but note that times can differ by several minutes over short distances.

Getting holidays, Torah readings, and Yahrzeits into your own calendar

Hebcal lets you download Jewish holidays and Hebrew dates to iPhone, iPad, Android (via Google Calendar), Outlook, macOS Desktop Calendar, or any app that supports iCalendar (.ics) feeds.

For personal dates:

  1. Create a list of Yahrzeit (memorial) and Yizkor dates, Hebrew birthdays, and anniversaries.
  2. The list can cover 20+ years.
  3. Free annual email reminders and calendar downloads are available for that list.

For Torah readings, you can get an aliyah-by-aliyah breakdown for the weekly parashah, plus spreadsheets intended for leyning coordinators.

Using Hebcal content on a website or app

Hebcal is part of the Open Source Judaism movement and offers JavaScript, JSON, and RSS APIs so you can embed its content directly — for example, on a synagogue website. The APIs are available under a Creative Commons Attribution (CC-BY) license. Site content is generally licensed under CC BY 4.0, with location data from GeoNames and MaxMind under Creative Commons as well.

Quick answers to common questions

Why does a Hebrew date move every year? Because the calendar is lunar-based with periodic leap months, so Hebrew dates shift against the Gregorian calendar while staying in the same season.

When does a Jewish day begin? At sunset the evening before, which is why candle-lighting times are listed for the day before the holiday or Shabbat date.

Can I get reminders instead of checking manually? Yes — Yahrzeit and related personal dates can generate free annual email reminders.

Do I need an account? The site shows a Sign in option, but the holiday calendars, date converter, Shabbat times, and Torah readings are presented as directly usable tools.