The main difference between the Gregorian calendar and the Jewish calendar is that the Gregorian calendar is a solar calendar based on the Earth’s orbit around the Sun, while the Jewish calendar is a lunisolar calendar based on both the moon’s phases and the solar year.
The Gregorian calendar has 12 fixed months and 365 or 366 days, used globally for civil purposes.
The Jewish (Hebrew) calendar, on the other hand, has 12 or 13 months, with each month starting on the new moon, and includes leap months to stay aligned with the solar year.
Comparison Table: Gregorian Calendar vs the Jewish Calendar
| Aspect | Gregorian Calendar | Jewish Calendar |
|---|---|---|
| Type | Solar | Lunisolar |
| Average Year Length | 365.24 days | 354 or 384 days |
| Leap Adjustment | Adds 1 day every 4 years | Adds 1 month every 2–3 years |
| Origin | 1582 CE (Pope Gregory XIII) | Biblical era |
| Month Length | 28–31 days | 29–30 days |
| New Year Begins | January 1 | 1 Tishrei |
| Day Begins | Midnight | Sunset |
| Religious Basis | None | Torah-based |
| Holiday Consistency | Fixed | Shifts relative to Gregorian dates |
Difference Between the Gregorian Calendar and the Jewish Calendar
What is the Gregorian Calendar?
The Gregorian calendar is the most widely used civil calendar in the world today.
It was introduced in 1582 by Pope Gregory XIII to correct inaccuracies in the Julian calendar.
This calendar is solar-based, meaning it measures time according to the Earth’s revolution around the Sun—a full cycle of roughly 365.2425 days.
Key features of the Gregorian calendar:
- 12 fixed months (January to December)
- 365 days in a common year, 366 in a leap year
- Leap year every 4 years (except centuries not divisible by 400)
- Basis for international civil, business, and digital systems
Learn more about how this calendar differs from lunar systems in our detailed guide on the Gregorian vs Lunar Calendar.
What is the Jewish Calendar?
The Jewish calendar, also known as the Hebrew calendar, is a lunisolar system that combines the moon’s cycles and the sun’s yearly pattern.
Each month begins with the new moon, and the year averages 12 lunar months, totaling about 354 days—around 11 days shorter than the solar year.
To stay in sync with the seasons, a leap month (Adar I) is added 7 times every 19 years.
Key characteristics of the Jewish calendar:
- 12 months in a normal year; 13 in a leap year
- Each month has 29 or 30 days, depending on moon cycles
- Based on ancient biblical and rabbinic calculations
- Primarily used for Jewish holidays, rituals, and festivals
You can explore the complete list of Jewish months to understand how each month aligns with the Gregorian calendar.
How the Two Calendars Count Time Differently
The Gregorian and Jewish calendars count time in completely different ways:
- Start of the Day:
- Gregorian days begin at midnight.
- Jewish days begin at sunset.
- Start of the Year:
- Gregorian year begins on January 1.
- Jewish year begins on 1 Tishrei (around September/October), marked by Rosh Hashanah.
- Length of Months:
- Gregorian months are fixed (28–31 days).
- Jewish months vary (29 or 30 days), based on moon phases.
- Leap Year Adjustment:
- Gregorian adds one day to February every 4 years.
- Jewish adds an entire extra month (Adar I) in leap years.
These differences explain why Jewish holidays, such as Passover or Hanukkah, fall on different Gregorian dates each year.
How to Convert Between Gregorian and Jewish Dates
- Use Gregorian to Jewish Calendar Converter to find the Hebrew date for any Gregorian day.
- Use Jewish to Gregorian Calendar Converter to find the civil date for any Hebrew day.
Religious vs. Civil Purposes
The Gregorian calendar serves civil, global, and secular needs.
It defines business years, school schedules, international dates, and technology systems.
The Jewish calendar, in contrast, serves religious and cultural purposes.
It determines:
- Dates for Jewish holidays (Yom Kippur, Purim, Hanukkah, Passover, etc.)
- Torah reading cycles
- Yahrzeits (memorial dates)
- Candle lighting and Sabbath times
Together, these calendars represent two systems of timekeeping — one universal and one faith-based.
FAQs – Difference Between the Gregorian and Jewish Calendar
What’s the main difference between the Gregorian and Jewish calendar?
The Gregorian calendar is solar, based on the Earth’s orbit around the Sun.
The Jewish calendar is lunisolar, based on both the moon’s cycles and the solar year.
How many months are in the Jewish calendar?
The Jewish calendar has 12 months in a regular year and 13 in a leap year.
(See the complete list of Jewish months for more details.)
Why don’t Jewish holidays fall on the same Gregorian date each year?
Because the Jewish calendar is lunar-based, its months don’t align perfectly with the solar Gregorian system, causing holiday dates to shift.
When does the Jewish day start?
Each Jewish day begins at sunset, unlike the Gregorian day which begins at midnight.
Can you convert Gregorian dates to Jewish dates?
Yes — you can easily do this with our Gregorian to Jewish Calendar Converter.
Final Thoughts
The difference between the Gregorian calendar and the Jewish calendar reflects more than just timekeeping — it reveals two distinct ways humanity connects with nature, faith, and history.
The Gregorian calendar follows the Sun’s precision for daily life, while the Jewish calendar follows the Moon’s rhythm for spiritual life.
Together, they show that time isn’t only measured in days — it’s also measured in meaning.
To explore more about world calendars and their unique structures, visit Types of Calendars on Jocalendars.com.