The Hijri Calendar: A Complete Guide to the 12 Islamic Months

The Islamic calendar — the Hijri calendar (at-taqwīm al-hijrī, التقويم الهجري) — is one of the oldest timekeeping systems still in use. Purely lunar, it organizes the religious life of 1.8 billion Muslims around the world. Understanding its mechanics, its months, and their spiritual virtues is essential for every believer who wants to live their Islam fully.

Key Points

• The Hijri calendar is a purely lunar calendar — 12 months of 29 or 30 days, totaling 354 days per year.
• It began with the Hijra — the migration of the Prophet ﷺ from Mecca to Medina in 622 CE.
• Four months are sacred (al-ashhur al-ḥurum): Muharram, Rajab, Dhul-Qa'da, and Dhul-Hijja.
• Each month begins with the observation of the crescent moon (hilāl).
• The Hijri year is 11 days shorter than the Gregorian year.
• Ramadan, Dhul Hijja, and Muharram carry particular spiritual graces.

Origin and History of the Hijri Calendar

The Hijra: Islam's Year Zero

The Islamic calendar begins in year 1 of the Hijra, corresponding to 622 CE. This year marks the migration (hijra, هجرة) of the Prophet ﷺ and his companions from Mecca to Medina — the founding event of the first organized Muslim community.

It was the caliph 'Umar ibn al-Khattāb (رضي الله عنه) who, in year 17 of the Hijra, officially established this calendar to unify the administration of the Islamic Empire. The chosen starting point was not the birth of the Prophet ﷺ nor the revelation of the Quran, but this founding social and political event: the Hijra.

Why a Lunar Calendar?

The Quran mentions the moon as a measure of time: "It is He who made the sun a radiance and the moon a light, and determined its phases that you might know the count of years and the reckoning." (Yunus 10:5)

And: "They ask you about the crescent moons. Say: They are timekeeping signs for people and for the pilgrimage." (Al-Baqara 2:189)

The lunar calendar directly links religious practices to celestial phenomena observable by the naked eye — accessible to everyone, everywhere in the world.

How the Hijri Calendar Works

The Lunar Structure

• 1 month = 29 or 30 days depending on observation of the crescent moon (hilāl)
• 1 year = 12 months = approximately 354 days
• Difference with the Gregorian calendar: approximately 11 days per year
• Result: each Islamic month shifts back about 11 days each Gregorian year
• In 33 years, the Islamic calendar completes one full cycle relative to the solar calendar

The Observation of the Hilāl

Traditionally, each Islamic month begins upon the sighting of the new moon (hilāl) with the naked eye. This practice has important practical implications:

• The start of Ramadan can vary from country to country
• National or local religious authorities announce the beginning of the month
• Some countries use predictive astronomical calculations

The Prophet ﷺ said: "Fast when you see it and break your fast when you see it. If it is obscured from you, complete thirty days." (Muslim, no. 1080 — sahih)

The 12 Islamic Months: Complete Details

1. Muharram (محرّم) — "The Sacred Month"

Meaning of the name: "Forbidden" — a month when wars were prohibited in pre-Islamic Arab tradition.

Status: Sacred (ḥarām) — one of the four sacred months.

Main virtue: The first month of the Hijri year. The Prophet ﷺ called it "the best fast after Ramadan." (Muslim, no. 1163 — sahih)

Key date: The 10th of Muharram is Ashura ('āshūrā', عاشوراء). The Prophet ﷺ said that fasting this day expiates the sins of the previous year. (Muslim, no. 1162 — sahih)

Recommended practice: Fast the 9th and 10th of Muharram (or the 10th and 11th).

2. Safar (صفر) — "The Empty Month"

Meaning of the name: "Empty" — houses were emptied during war expeditions.

Status: Ordinary month.

Spiritual note: Some superstitious minds associate Safar with bad luck. Islam rejects all forms of superstition (tafā'ul): the Prophet ﷺ stated: "There are no bad omens." (Bukhari, no. 5707 — sahih)

3. Rabi' al-Awwal (ربيع الأول) — "The First Spring"

Meaning of the name: First month of "spring" in the ancient Arab nomenclature.

Status: Ordinary month, but one of great spiritual significance.

Key date: The 12th of Rabi' al-Awwal (according to the majority Sunni tradition) is the birth date of the Prophet Muhammad ﷺ — celebrated in many countries as the Mawlid an-Nabī (المولد النبوي).

4. Rabi' al-Thani (ربيع الثاني) — "The Second Spring"

Meaning of the name: Second month of "spring."

Status: Ordinary month.

5. Jumada al-Ula (جمادى الأولى) — "The First Month of Freezing"

Meaning of the name: "Freezing" — referring to the cold season of ancient Arabia.

Status: Ordinary month.

6. Jumada al-Akhira (جمادى الآخرة) — "The Second Month of Freezing"

Meaning of the name: Second freezing month.

Status: Ordinary month.

7. Rajab (رجب) — "The Month of Respect"

Meaning of the name: From the verb rajaba — "to respect," "to venerate."

Status: Sacred (ḥarām) — one of the four sacred months.

Key date: The 27th of Rajab is commemorated in many traditions as the night of Isra' wal-Mi'raj (الإسراء والمعراج) — the Prophet's ﷺ night journey and ascension to the heavens.

Recommended practice: Increase prayers, voluntary fasting, and Quran reading in this blessed month.

8. Sha'ban (شعبان) — "The Month of Expansion"

Meaning of the name: From the verb sha'aba — "to spread," referring to Arab tribes dispersing to find water.

Status: Ordinary month, but the Prophet ﷺ fasted abundantly in it.

Main virtue: The Prophet ﷺ said: "Sha'ban is a month that people neglect between Rajab and Ramadan. It is a month in which deeds are presented to the Lord of the worlds, and I love for my deeds to be presented while I am fasting." (Nasai, no. 2357 — hasan)

Key date: The night of the 15th of Sha'ban (Laylat an-Niṣf min Sha'bān) is a night of particular grace according to many scholars.

9. Ramadan (رمضان) — "The Month of Intense Heat"

Meaning of the name: From the verb ramaḍa — "to burn" — the intense summer heat of Arabia.

Status: The sacred month par excellence — the month of obligatory fasting.

Main virtue: Allah says: "The month of Ramadan is the one in which the Quran was revealed." (Al-Baqara 2:185)

The Prophet ﷺ said: "When Ramadan arrives, the gates of Paradise are opened, the gates of Hell are closed, and the devils are chained." (Bukhari, no. 1899 — sahih)

Characteristics of Ramadan:

• Obligatory fast from dawn to sunset
• Tarāwīḥ (التراويح) night prayers
• The night of Laylat al-Qadr (ليلة القدر — Night of Destiny) in the last 10 days — better than a thousand months (Al-Qadr 97:3)
• I'tikāf (الاعتكاف — spiritual retreat) during the last 10 days

10. Shawwal (شوال) — "The Month of Lifting"

Meaning of the name: Referring to she-camels that were pregnant.

Status: Ordinary month — but begins with Eid al-Fitr.

Key date: The 1st of Shawwal is Eid al-Fitr ('Īd al-Fiṭr, عيد الفطر) — the feast of breaking the fast.

Recommended practice: The Prophet ﷺ said: "Whoever fasts Ramadan and then follows it with six days of Shawwal, it is as if he fasted for the whole year." (Muslim, no. 1164 — sahih)

11. Dhul-Qa'da (ذو القعدة) — "The Month of Rest"

Meaning of the name: From the verb qa'ada — "to sit," "to rest" — a month when fighting ceased.

Status: Sacred (ḥarām) — one of the four sacred months. Month of preparation for Hajj.

12. Dhul-Hijja (ذو الحجة) — "The Month of Pilgrimage"

Meaning of the name: "The one of pilgrimage" — the month of Hajj.

Status: Sacred (ḥarām) and spiritually the most charged of the year alongside Ramadan.

Main virtues: The Prophet ﷺ said: "There are no days in which righteous deeds are more beloved to Allah than these ten days of Dhul-Hijja." (Bukhari, no. 969 — sahih)

Key dates:

• 1–9 Dhul-Hijja: the blessed ten days — recommended to fast, make dhikr, give in charity
• 8 Dhul-Hijja: Yawm at-Tarwiya (يوم التروية) — beginning of Hajj
• 9 Dhul-Hijja: Day of Arafah (Yawm 'Arafah) — the Prophet ﷺ said fasting this day expiates the sins of the previous and coming years (Muslim, no. 1162 — sahih)
• 10 Dhul-Hijja: Eid al-Adha ('Īd al-Aḍḥā, عيد الأضحى) — the feast of sacrifice

The Four Sacred Months in Detail

Allah says: "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." (At-Tawba 9:36)

In these months, virtuous acts are multiplied — and sins also carry greater weight. Scholars recommend increased spiritual vigilance.

How to Convert a Hijri Date to a Gregorian Date

The Simple Rule

The Hijri year is approximately 11 days shorter than the Gregorian year (354 days vs. 365). For a quick approximation:

From Gregorian to Hijri:

Hijri year ≈ (Gregorian year − 622) × 1.031

From Hijri to Gregorian:

Gregorian year ≈ (Hijri year × 0.970) + 622

Concrete Examples

The Islamic Calendar in Modern Daily Life

Practical Uses

In Muslim-majority countries, the Hijri calendar coexists with the Gregorian:

• Civil calendar uses the Gregorian system
• Religious holidays follow the Hijri calendar
• Contracts, financial decisions, and administrative acts use both dates

For Muslims in the West

Knowing the Hijri calendar allows you to:

• Anticipate Ramadan and prepare your employer
• Plan the Hajj well in advance
• Practice voluntary fasts (Ashura, Arafah)
• Celebrate both Eids in community

The Muslim Expert app (available here) integrates a complete Islamic calendar with automatic Gregorian ↔ Hijri date conversion, reminders for key Islamic events, and display of lunar months.

Blessed Nights and Days Not to Miss

Frequently Asked Questions (FAQ)

Why does the start of Ramadan vary between countries?

The beginning of each month depends on the sighting of the crescent moon (hilāl). This sighting can vary depending on geographic location and weather conditions. Some countries announce the start of the month based on their own national observation, others follow Saudi Arabia, or use predictive astronomical calculation.

What is the difference between the two Eids?

Eid al-Fitr (1 Shawwal) marks the end of Ramadan's fast. Eid al-Adha (10 Dhul-Hijja) commemorates the sacrifice of Ibrahim (عليه السلام) and coincides with the end of Hajj. Both are obligatory celebrations with communal prayer.

How do you correctly write a Hijri date?

A Hijri date is written: Day / Month / Year H. Example: 1 Ramadan 1446 H. In Arabic, "هـ" (for هجري) is added after the year.

Is the Hijri calendar universally accepted by Muslims?

The structure of the 12 months is universally accepted. Divergences concern the method for determining the start of the month (local vs. global lunar observation vs. astronomical calculation). These divergences are an area of research and dialogue among scholars.

Going Further

• Our article on Ramadan: Complete Guide
• Our article on Hajj and Umra
• Check prayer times to integrate Islamic times into your daily life

May Allah grant us to experience the blessed moments of His calendar in worship, gratitude, and piety. Āmīn