How the Hijri calendar works
The Hijri (Islamic) calendar is a lunar calendar. It counts years from the Hijrah, the Prophet’s migration from Makkah to Madinah in 622 CE. Each month begins with the new crescent moon and lasts 29 or 30 days. Twelve months make a year of 354 or 355 days, about 11 days shorter than the Gregorian year.
Because of that gap, Islamic dates move through the seasons. Ramadan starts about 11 days earlier each Gregorian year and goes all the way round the seasons in roughly 33 years.
The formula above only gives the rough year. For exact days the converter uses one of two calendars.
Umm al-Qura and the tabular calendar
- Umm al-Qura is Saudi Arabia’s official calendar. Months are set by astronomical rules about the new moon and moonset over Makkah, so dates are known in advance. Many Gulf countries use it for official purposes. The converter reads it from your browser’s built-in calendar data (the same ICU data used by Android, Chrome, Safari and Firefox), which covers 1300 to 1600 AH.
- The tabular Islamic calendar uses a fixed pattern instead of the moon: months alternate 30 and 29 days, and 11 years in every 30 get an extra day. It is simple and works for any date, but can be a day or two off the real moon.
From Gregorian to Hijri, the converter asks your browser’s calendar for the date. From Hijri to Gregorian, it starts from the tabular estimate and checks the days around it until it finds the matching Umm al-Qura date.
Why Pakistan’s date can be a day behind
In Pakistan, the Ruet-e-Hilal Committee declares the start of each month only after the new moon has actually been seen. India and Bangladesh also rely on local sighting. The young moon is often visible a day later in South Asia than the Umm al-Qura calculation assumes. So Ramadan, Eid and Muharram often begin one day after Saudi Arabia.
Use the moon sighting adjustment to match your local calendar. If your month started a day after Saudi Arabia, choose “1 day later” and every date is shifted to match. Always follow the official announcement for Eid and the start of Ramadan; the converter can only show expected dates.
Hijri months
| No. | Month | Urdu spelling | Notes |
|---|---|---|---|
| 1 | Muharram | Muharram | Islamic New Year; Ashura on the 10th |
| 2 | Safar | Safar | |
| 3 | Rabi al-Awwal | Rabi ul Awwal | 12th widely marked as the Prophet’s birthday |
| 4 | Rabi al-Thani | Rabi us Sani | |
| 5 | Jumada al-Ula | Jamadi ul Awwal | |
| 6 | Jumada al-Akhirah | Jamadi us Sani | |
| 7 | Rajab | Rajab | |
| 8 | Shaban | Shaban | |
| 9 | Ramadan | Ramzan | Month of fasting |
| 10 | Shawwal | Shawwal | Eid ul Fitr on the 1st |
| 11 | Dhu al-Qadah | Zul Qadah | |
| 12 | Dhu al-Hijjah | Zul Hijjah | Hajj; Eid ul Adha on the 10th |
Worked examples
- 18 February 2026 is 1 Ramadan 1447 AH in the Umm al-Qura calendar. If the moon is seen a day later in Pakistan, the first fast there falls on 19 February.
- 26 June 2025 is 1 Muharram 1447 AH, the Islamic New Year.
- 1 Ramadan 1447 converted back gives Wednesday, 18 February 2026, and the converter tells you whether that Ramadan has 29 or 30 days in the calendar.
Tips and edge cases
- A Hijri day starts at sunset. The evening before a Gregorian date is already the next Hijri day in Islamic practice. The converter matches whole days, the way calendars print them.
- Old documents. Dates before 1300 AH (1882) use the tabular calendar, so treat them as accurate to within a day or two. Historical records may also have used local sighting.
- Hijri dates of birth. Saudi documents often give a Hijri date of birth. Convert it here, then use the age calculator to work out your exact age.
- Zakat year. Zakat is due after one Hijri year. Pick your anniversary here and work out the amount with the zakat calculator.
- Counting days. To count the days between two Gregorian dates, use the date calculator.
Your dates are converted in your browser and are not sent anywhere.