What is the Hijri calendar?
The Hijri calendar is the lunar calendar Muslims use to fix religious dates — Ramadan, the two Eids, Hajj, Ashura, and every other anchor of Islamic worship. The Quran establishes the count of twelve months as a divine decree: “Indeed, the number of months with Allah is twelve months in the register of Allah from the day He created the heavens and the earth” (Quran 9:36).
Year 1 AH begins on the day of the Hijra — the migration of the Prophet Muhammad ﷺ from Makkah to Madinah, dated 16 July 622 CE in the Julian calendar (19 July 622 CE Gregorian). The migration didn't start the calendar that year; it was adopted retroactively by the second caliph, Umar ibn al-Khattab, around 17 AH (638 CE) as a unifying civil dating system for the rapidly growing Muslim state.
The choice of the Hijra — rather than the Prophet's birth or the first revelation — was deliberate. The companions debated the question and Umar, on Ali ibn Abi Talib's recommendation, picked the Hijra because it marked the founding of the first Muslim community. It's a calendar that begins not with a person but with a community.
That's also why “Hijri” and “Islamic calendar” mean the same thing in modern usage. Older Western texts sometimes call it the “Muhammadan calendar” — that name is inaccurate and out of use.
How the Hijri calendar works
A Hijri month begins with the sighting of the new crescent moon (hilal) at sunset and runs until the next crescent — usually 29 or 30 days. Twelve such months add up to roughly 354.367 days, which is why a Hijri year is fixed at 354 days in eleven years out of every thirty, and 355 days in the other nineteen “leap” years.
The Prophet Muhammad ﷺ tied the rhythm of the calendar directly to observation: “The month consists of twenty-nine nights, so do not fast till you have sighted the crescent. And if the sky is cloudy, then complete thirty days” (Narrated by Ibn Umar, Sahih al-Bukhari 1907). That single instruction is the basis for the entire Hijri month structure — every month must be 29 or 30 days, never less, never more.
Because the lunar year is around 10.87 days shorter than the solar Gregorian year, every Islamic date shifts backward through the seasons. A child born on 1 Ramadan today will see Ramadan move through every season of their lifetime — winter, autumn, summer, spring — and return to the same Gregorian season after roughly 33 solar years.
This is the calendar's design, not a quirk. A lunar count keeps the months synchronized with the moon's actual phases, so when a Muslim in Lagos, Lahore, or Jakarta looks up at the crescent on the 1st of Muharram, the moon's phase is the same. That visual unity is part of why the Prophet ﷺ said: “We are an unlettered nation; we neither write nor calculate. The month is like this and this” — gesturing 29 then 30 with his fingers (Sahih al-Bukhari 1913).
The 12 Hijri months
The Hijri year follows a fixed order. Four of these — marked sacred — get special protection in Islamic law: warfare is forbidden, and the reward for righteous deeds is multiplied.
1. Muharram — مُحَرَّمsacred
Muharram means “forbidden” — its sanctity dates to pre-Islamic Arabia, where fighting was prohibited during this month. The 10th of Muharram is the Day of Ashura, on which Prophet Musa (Moses) and the Children of Israel were saved from Pharaoh. The Prophet ﷺ recommended fasting Ashura, ideally with the 9th (Tasu'a) added to distinguish it from Jewish practice ( Sahih Muslim 1134).
2. Safar — صَفَر
Safar's name probably derives from “empty,” referring to pre-Islamic raids that emptied homes during this month. Pre-Islamic Arabs considered Safar unlucky; the Prophet ﷺ explicitly rejected this superstition: “There is no Safar (i.e., no ill-omen in the month of Safar)” ( Sahih al-Bukhari 5757). Safar contains no major obligatory observances, which makes it one of the most misunderstood months.
3. Rabi al-Awwal — رَبيع الأوّل
“The first spring,” named for when the month originally fell in the season. This is the month the Prophet Muhammad ﷺ was born — most historians place his birth on 9 or 12 Rabi al-Awwal in the Year of the Elephant (around 570 CE). It's also the month of his arrival in Madinah, founding the first Muslim state. Observance of Mawlid on the 12th varies between scholars.
4. Rabi al-Thani — رَبيع الثَّاني
Also called Rabi al-Akhir (“the last spring”), it follows Rabi al-Awwal in the seasonal pairing. The month is quiet in the Islamic calendar — no major mandated observances. Some traditions associate it with the death anniversary of Shaykh Abdul Qadir al-Jilani (11th of Rabi al-Thani), commemorated in parts of South Asia.
5. Jumada al-Awwal — جُمادى الأولى
“The first of dry/parched months” — the name comes from jamada, “to freeze” or “harden,” reflecting the dry, cold weather when the month was originally named. Like its pair, Jumada has no obligatory Islamic observances. It's a month for steady, ordinary worship — the kind of consistency the Prophet ﷺ called most beloved to Allah.
6. Jumada al-Thani — جُمادى الآخِرة
Sometimes called Jumada al-Akhirah. It completes the dry pair and leads into Rajab, the start of the sacred sequence later in the year. The Prophet's daughter Fatimah al-Zahra (RA) passed away in this month, six months after her father. South Asian Muslim communities often observe her memorial on the 3rd.
7. Rajab — رَجَبsacred
The first of the sacred months in the calendar year. The name comes from rajaba, “to respect” or “honor.” Rajab is the month of Isra and Mi'raj— the Prophet's ﷺ night journey from Makkah to Jerusalem and his ascent through the heavens, during which the five daily prayers were prescribed. Most scholars date Isra and Mi'raj to the 27th of Rajab, though the historical record is not definitive.
8. Sha'ban — شَعْبان
“To scatter” or “branch out” — the month when pre-Islamic Arabs would scatter in search of water before the heat of Ramadan. Sha'ban is the Prophet's ﷺ preferred month for voluntary fasting outside Ramadan: “I never saw the Messenger of Allah fast a complete month except Ramadan, and I never saw him fast more in any month than in Sha'ban” (Narrated by A'ishah, Sahih al-Bukhari 1969). The 15th of Sha'ban (Laylat al-Bara'ah / Shab-e-Barat) holds significance for many South Asian Muslims.
9. Ramadan — رَمَضان
“Scorching heat” — the most well-known Hijri month, when fasting from dawn to sunset is obligatory for every adult Muslim in good health (Quran 2:185). Ramadan also contains Laylat al-Qadr— the Night of Decree, which the Quran describes as “better than a thousand months” (Quran 97:3). It's commonly sought in the last ten nights, especially the odd ones. The month ends with Eid al-Fitr.
10. Shawwal — شَوّال
“To lift” or “carry” — the month that opens with Eid al-Fitron the 1st. The Prophet ﷺ recommended six additional days of fasting in Shawwal: “Whoever fasts Ramadan and follows it with six days of Shawwal, it is as if he has fasted the whole year” ( Sahih Muslim 1164). These can be consecutive or spread throughout the month.
11. Dhu al-Qi'dah — ذو القَعْدةsacred
“The one of sitting” — named for the pre-Islamic custom of “sitting out” of warfare during this sacred month. It's the lead-in to Hajj season; pilgrims travel and prepare during this month. Three of the Prophet's ﷺ four Umrahs took place in Dhu al-Qi'dah, marking it as a month of pilgrimage even outside Hajj proper.
12. Dhu al-Hijjah — ذو الحِجّةsacred
“The one of Hajj” — the month containing the Hajj pilgrimage (8th–13th) and Eid al-Adha(10th). The first ten days are described in hadith as the most beloved days of the year for righteous deeds ( Sahih al-Bukhari 969). The 9th — the Day of Arafah — is the spiritual peak of Hajj; for non-pilgrims, fasting Arafah expiates the previous year's and the coming year's sins ( Sahih Muslim 1162).
The four sacred months (ashhur al-hurum)
Four of these twelve months are designated al-ashhur al-hurum — the sacred months — and the Quran is explicit about it:
“Indeed, the number of months with Allah is twelve months in the register of Allah from the day He created the heavens and the earth; of these, four are sacred. That is the correct religion, so do not wrong yourselves during them.”
The Prophet ﷺ identified them by name in his Farewell Sermon: “The year is twelve months, four of which are sacred: three consecutive — Dhu al-Qi'dah, Dhu al-Hijjah, and Muharram — and Rajab of Mudar, which is between Jumada and Sha'ban” (Sahih al-Bukhari 4662). For an overview of these four months as a group, see our guide to the four sacred months in Islam.
What does “sacred” actually mean in practice? Two things. First, warfare is prohibited during these months unless one is defending against an attack — a rule that pre-dates Islam and was preserved by the Quran. Second, scholars across schools of thought agree that the reward for righteous deeds — and the gravity of sins — is multiplied during sacred months. As Ibn Abbas explained, “He [Allah] singled out four of them as sacred, magnified their inviolability, and made sin in them greater and righteous deeds in them more rewarded.”
Three of the four sit together (Dhu al-Qi'dah, Dhu al-Hijjah, Muharram), creating a 90-day cluster of heightened spiritual significance — a deliberate alignment of Hajj season with the months of pilgrimage. Rajab stands alone, six months later, as a mid-year reset.
Moon sighting vs astronomical calculation
This is the most contentious question in the Hijri calendar — and the reason Ramadan and Eid sometimes start on different days in different countries. The Prophet ﷺ instructed: “Fast when you see it [the crescent], and break your fast when you see it” (Sahih al-Bukhari 1909, Sahih Muslim 1080). The question is what “see” means in the 21st century.
The majority Sunni position — local moon sighting (ru'yah hilal):The new month doesn't begin until a credible witness physically sights the crescent moon at sunset. If no sighting is possible (clouds, low horizon, weather), the previous month is completed at 30 days. This is the official method in Pakistan, India, Bangladesh, Indonesia, Malaysia, Morocco, and most Muslim-majority states.
The Saudi position — Umm al-Qura calculation with sighting confirmation: Saudi Arabia's Umm al-Qura calendar is calculated using astronomical criteria — a date is fixed in advance based on whether the moon is born before sunset at Makkah and sets after the sun. Sighting reports from a national committee can still adjust the start of religious months (especially Ramadan and Dhu al-Hijjah for Hajj). See the official Umm al-Qura calendar for reference.
Modern computational positions:The European Council for Fatwa and Research and the Fiqh Council of North America accept astronomical calculation as a valid basis for fixing month starts, citing the precision of modern lunar science. They argue that the Prophet's ﷺ direction to look for the crescent reflected the means of his time, not a permanent rule against calculation.
Why this matters for you:Two Muslims in the same city might disagree on the first day of Ramadan because they follow different authorities. There's no single right answer that all scholars accept. The most practical approach: follow your local masjid or national sighting committee, recognize that other communities making different choices are also acting on valid scholarly opinion, and avoid the sectarianism that sometimes attaches to this discussion.
For day-to-day reference — knowing today's Hijri date or converting a birthday — the calculated calendar in the converter above is more than accurate enough. For Ramadan and Eid, defer to whoever your community defers to.
Why does Ramadan move earlier every year?
Because the Hijri year is around 10.87 days shorter than the Gregorian year. A lunar year is 354 or 355 days; a Gregorian year is 365 or 366. Every Gregorian year, every Hijri date — including 1 Ramadan, the Day of Arafah, and Ashura — shifts roughly 11 days earlier on the Gregorian calendar.
Over a single decade, that's about 110 days — more than three months. Ramadan in 2026 falls in February; ten years earlier it fell in June. After roughly 33 solar years, the Hijri date cycles all the way back to the same Gregorian month — every Muslim who lives 70 years experiences Ramadan in every season twice.
Is this a flaw? It was deliberate. Quran 9:36–37 explicitly condemns nasi' — the pre-Islamic practice of intercalating an extra month to keep months in fixed seasons. By rejecting intercalation, the Hijri calendar guarantees that the obligations attached to specific months — the heat-of-summer fast, the cold-of-winter fast, Hajj in spring or autumn — rotate through every climate.
For a Muslim in Lagos, Karachi, or Manila, this means Ramadan never settles into a permanent season. The test of the long summer fast becomes the gift of the short winter fast a decade later. That cycling is a feature of the calendar's design, not a bug.
Using this Hijri calendar tool
The converter at the top of this page handles both directions — pick any Gregorian date to see its Hijri equivalent, or flip to enter a Hijri date and find the Gregorian. Today's Hijri date is shown at the top so you don't need to type anything to get the current Islamic date.
A practical tip: bookmark this page if you're planning around Ramadan, Hajj, or a memorial date — converted dates are accurate to the Umm al-Qura calendar that powers most digital systems. Pair it with prayer times for daily worship and the Qibla compass for travel, and you have the three timing tools every Muslim needs in one place. If you want to deepen your daily practice further, our 99 Names of Allah collection is a quiet companion for any month of the year.