The main difference between the Gregorian calendar and the lunar calendar is that the Gregorian calendar is based on the solar year (365 days, aligned with Earth’s orbit around the Sun), while the lunar calendar is based on lunar months (29–30 days, aligned with the Moon’s phases).
This means the Gregorian calendar stays consistent with the seasons, while the lunar calendar shifts over time unless adjusted.
Overview:
- Gregorian calendar: 12 months, 365 or 366 days
- Lunar calendar: 12–13 months, 354 or 355 days
- Use today: Gregorian (global standard); Lunar (religious & cultural events)
What is the Gregorian Calendar?
The Gregorian calendar is the most widely used civil calendar worldwide.
- Introduced by Pope Gregory XIII in 1582.
- Corrected the drift of the Julian calendar.
- Keeps Easter and other Christian holidays in line with the solar year.
What is the Lunar Calendar?
The lunar calendar tracks time by the Moon’s phases.
- A lunar month = 29.5 days.
- A lunar year = about 354 days.
- Common in Islamic (Hijri), Hebrew, and Chinese calendars.
Comparison Table: Gregorian vs Lunar Calendar
| Feature | Gregorian Calendar | Lunar Calendar |
|---|---|---|
| Basis | Solar year (Earth’s orbit) | Lunar months (Moon’s phases) |
| Year length | 365 or 366 days | 354 or 355 days |
| Months | 12 fixed months | 12–13 variable months |
| Drift over time | Minimal (corrected with leap year) | Shifts ~11 days per year |
| Modern use | Global civil standard | Religious & cultural observances |
Also see: Ethiopian to Gregorian Calenda Conversion
What is the main difference between a lunar and Gregorian calendar?
The Gregorian calendar is solar-based, while the lunar calendar is moon-based.
How many days are in a lunar year compared to a Gregorian year?
A lunar year has about 354 days, while a Gregorian year has 365 or 366 days.
Why does the Islamic calendar use lunar months?
It follows the Hijri system, which is based solely on the Moon’s cycle to mark Islamic holidays like Ramadan.
When does the lunar calendar add an extra month?
In the Chinese calendar, an extra leap month is added every 2–3 years to realign with the solar year.
Which calendar is more accurate: lunar or Gregorian?
The Gregorian calendar is more accurate for keeping track of seasons, but the lunar calendar is essential for cultural and religious traditions.