Hijri Calendar vs Gregorian Calendar: Key Differences
Many people wonder about the exact differences between the Hijri and Gregorian calendars. This article breaks down those differences clearly and concisely.
Lunar vs Solar: The Core Difference
The fundamental difference is the astronomical basis. The Hijri calendar is lunar, tracking the Moon's orbit around the Earth. The Gregorian calendar is solar, tracking the Earth's orbit around the Sun. This single difference drives most of the other distinctions between the two systems.
Number of Days Per Year
A Hijri year contains 354 days (or 355 in a leap year). A Gregorian year contains 365 days (or 366). The gap of roughly 11 days means that Islamic observances advance about 11 days earlier each year in Gregorian terms. After approximately 33 Gregorian years, the cycle completes and the Hijri calendar has moved through all seasons.
Historical Starting Point
The Gregorian calendar counts from Year 1, associated with the birth of Jesus Christ. The Hijri calendar counts from 622 CE, the year of the Prophet Muhammad's ﷺ migration from Mecca to Medina. As a result, the current Hijri year is approximately 578–579 years behind the Gregorian year.
How Months Begin
In the Gregorian calendar, each month begins on a fixed date determined by mathematical calculation — January always starts on the 1st. In the Hijri calendar, each month traditionally begins with the sighting of the new crescent moon, which can vary by a day between countries depending on observation conditions.
Uses in Daily Life
The Gregorian calendar is used for civil, commercial, and international affairs worldwide. The Hijri calendar is used primarily for: Islamic worship timings, religious holidays, official documents in some Muslim-majority countries, and Islamic legal rulings. Countries like Saudi Arabia officially use both calendars simultaneously.
Quick Comparison
| Feature | Hijri | Gregorian |
|---|---|---|
| Basis | Lunar | Solar |
| Days per year | 354–355 | 365–366 |
| Starting point | 622 CE (Hijra) | 1 CE (Birth of Christ) |
| Month start | Crescent moon sighting | Fixed calculation |