The Islamic (Hijri) Calendar
The Islamic calendar, also known as the Hijri calendar (التقويم الهجري), is a purely lunar calendar used by Muslims worldwide to determine the dates of religious observances. It has 12 months and approximately 354–355 days per year—about 11 days shorter than the solar (Gregorian) calendar. This is why Ramadan, Eid, and Hajj shift earlier each year in the Gregorian calendar.
Quranic Foundation
"Indeed, the number of months with Allah is twelve [lunar] months in the register of Allah [from] the day He created the heavens and the earth; of these, four are sacred." (Surah At-Tawbah 9:36)
Origin: The Hijrah The Islamic calendar begins from the Hijrah—the migration of the Prophet (peace be upon him) from Mecca to Medina in 622 CE. The first year of the Hijri calendar (1 AH) marks this pivotal event. Caliph Umar ibn al-Khattab established this dating system during his reign.
The 12 Months
| # | Arabic | Name | Notes |
|---|---|---|---|
| 1 | مُحَرَّم | Muharram | Sacred month; Islamic New Year |
| 2 | صَفَر | Safar | "Empty" |
| 3 | رَبِيع ٱلْأَوَّل | Rabi al-Awwal | Prophet's birth month |
| 4 | رَبِيع ٱلثَّانِي | Rabi al-Thani | Second spring |
| 5 | جُمَادَىٰ ٱلْأُولَىٰ | Jumada al-Awwal | First Jumada |
| 6 | جُمَادَىٰ ٱلثَّانِيَة | Jumada al-Thani | Second Jumada |
| 7 | رَجَب | Rajab | Sacred month; Isra' and Mi'raj |
| 8 | شَعْبَان | Sha'ban | Preparation before Ramadan |
| 9 | رَمَضَان | Ramadan | Month of fasting |
| 10 | شَوَّال | Shawwal | Eid ul-Fitr (1st) |
| 11 | ذُو ٱلْقَعْدَة | Dhul Qa'dah | Sacred month |
| 12 | ذُو ٱلْحِجَّة | Dhul Hijjah | Sacred month; Hajj (10th) |
The Four Sacred Months Muharram, Rajab, Dhul Qa'dah, and Dhul Hijjah are the four sacred months in which warfare was traditionally forbidden. Allah says: "So do not wrong yourselves during them." (9:36)
Key Dates - 1 Muharram — Islamic New Year - 10 Muharram — Day of Ashura (fasting recommended) - 12 Rabi al-Awwal — Prophet's birthday (Mawlid) - 27 Rajab — Isra' and Mi'raj (night journey) - 1 Ramadan — Start of fasting - 1 Shawwal — Eid ul-Fitr - 10 Dhul Hijjah — Eid ul-Adha (Day of Sacrifice)
Hijri vs. Gregorian Calendar
| Aspect | Islamic (Hijri) | Gregorian |
|---|---|---|
| Basis | Lunar (moon phases) | Solar (Earth around sun) |
| Year length | ~354–355 days | 365 days (366 in leap year) |
| Starting point | Hijrah (622 CE) | Birth of Jesus (1 CE) |
| Month length | 29 or 30 days (varies by moon sighting) | 28–31 days (fixed) |
| Month start | New moon sighting | Fixed calendar date |
| Seasonal drift | Dates shift ~11 days earlier each year | Dates stay fixed in seasons |
Each Hijri month begins when the new moon is sighted. Because the lunar year is about 11 days shorter than the solar year, Islamic dates move backward through the seasons over a 33-year cycle—so Ramadan may fall in winter one decade and in summer another. The Gregorian calendar, by contrast, keeps the same dates in the same seasons (e.g., January is always winter in the Northern Hemisphere). This reflects the Quranic emphasis on the moon for marking time: "They ask you about the new moons. Say: They are measurements of time for the people and for Hajj." (2:189)