How to Convert a Gregorian Date to Hijri — and Why the Islamic Date Can Differ by a Day
Daily life in Pakistan runs on two calendars at once. Offices, schools and banks use the Gregorian calendar, while Ramadan, Eid, Hajj and other religious observances follow the Hijri calendar — and the two rarely line up for long. Converting a date between them is a common need, so this guide explains how the Hijri calendar works, why its dates move every year, and why a converted date can differ by a day from the date observed in Pakistan.
For an instant answer, use the Hijri Date Converter: pick any Gregorian date and it shows the Hijri day, month name and year AH, together with the Gregorian date and weekday. The rest of this guide explains what the converter is doing.
Two Calendars, Two Different Years
The Gregorian calendar is a solar calendar: its year of 365 days, 366 in a leap year, follows the seasons, and it is the standard civil calendar in most of the world. The Hijri calendar is a lunar calendar: its year is built from 12 cycles of the moon and lasts 354 days in an ordinary year and 355 days in a leap year.
The Hijri era counts from the Hijra, the migration of the Prophet Muhammad (peace be upon him) from Makkah to Madinah in 622 CE, the first year of the calendar. That is why Hijri years are written with AH after them, short for Anno Hegirae, ‘in the year of the Hijra’.
Because the lunar year is shorter, about 33 Hijri years pass in the time of roughly 32 Gregorian years, so the two year numbers slowly draw closer together over the centuries.
Why Islamic Dates Move About 11 Days Earlier Each Year
A lunar year of 354 days is about 11 days shorter than a solar year of 365 days. The result is simple: every Gregorian year, each Islamic date falls roughly 11 days earlier than it did the year before. A date that fell on 22 October one year falls around 11 October the next, then around 30 September the year after.
That is why Ramadan is not fixed to a season. Over roughly three decades it travels through the whole Gregorian year, falling in winter for some years, then in autumn, then in high summer. It also means a Hijri birthday arrives a little ‘early’ every year in Gregorian terms, which is why an age worked out in Hijri years is always slightly higher than the same age in Gregorian years.
The 12 Hijri Months
The months follow the moon, alternating between 30 and 29 days in the calculated calendar. In a leap year the final month, Dhul Hijjah, gains a thirtieth day, bringing the year to 355 days.
| No. | Month | Days |
|---|---|---|
| 1 | Muharram | 30 |
| 2 | Safar | 29 |
| 3 | Rabi al-Awwal | 30 |
| 4 | Rabi al-Thani | 29 |
| 5 | Jumada al-Awwal | 30 |
| 6 | Jumada al-Akhirah | 29 |
| 7 | Rajab | 30 |
| 8 | Shaban | 29 |
| 9 | Ramadan | 30 |
| 10 | Shawwal | 29 |
| 11 | Dhul Qadah | 30 |
| 12 | Dhul Hijjah | 29 (30 in leap years) |
Some months are widely known. Muharram opens the Islamic year, and its tenth day is Ashura. Ramadan, the ninth month, is the month of fasting. Shawwal begins with Eid al-Fitr, and Dhul Hijjah is the month of Hajj and Eid al-Adha.
How to Convert a Date, Step by Step
- Open the Hijri Date Converter.
- Choose the Gregorian date in the date field, or press the Today button to fill in the current date.
- Press Convert to Hijri.
- Read the result: the Hijri day, month name and year AH, shown with the Gregorian date and its weekday.
Worked Example
Take 22 October 2026. The converter gives 10 Jumada al-Awwal 1448 AH, and the Gregorian line confirms the day was a Thursday. On that occasion the calculated date also matched the Hijri date being observed in Pakistan. A second check: 1 January 2025 converts to 1 Rajab 1446 AH.
Calculated Calendar vs Moon Sighting: Why a Day Can Differ
There are two ways to fix a Hijri date. The calculated, or tabular, calendar follows fixed arithmetic rules: the months alternate 30 and 29 days and leap years fall on a set cycle, so any date, past or future, can be worked out exactly. This is the calendar built into modern browsers and phones (its technical name is islamic-civil), and it is the one the converter uses.
Pakistan, however, officially starts each Islamic month when the new crescent moon is sighted, as announced by the Ruet-e-Hilal Committee. Whether the crescent is seen on the twenty-ninth evening depends on the moon’s position, the weather and haze, so the observed month can begin a day later than the calculated date — and occasionally the two agree exactly, as they did in the worked example above.
In practice, use the calculated date for planning, paperwork and conversions, and the Ruet-e-Hilal announcement for the religious observance itself. A difference of one day between the two is normal and expected; it does not mean that either date is wrong.
When You Need a Conversion
Conversions come up more often than most people expect:
- Ramadan, Eid and Hajj planning: families book leave, travel and events in Gregorian diaries for dates that are fixed in Hijri.
- Zakat anniversaries: Zakat becomes due after a full lunar year on qualifying savings, so many people fix their Zakat date in Hijri and convert it each year. The Zakat Calculator then works out the amount.
- Birthdays and documents: older family records and some documents give Hijri dates of birth. Convert first, then the Age Calculator works out an exact age in years, months and days.
- Counting days between dates: to measure the gap between two Gregorian dates, for a deadline or an anniversary, the Date Difference Calculator counts the days for you.
Frequently Asked Questions
Is the calculated Hijri date exact?
It is exact within the rules of the calculated calendar, and it is the date most calendars and devices will show. The date observed in Pakistan, though, follows moon sighting and can differ by one day, so follow the Ruet-e-Hilal announcement for religious observance.
Why does Ramadan start earlier every year?
Because the lunar year is about 11 days shorter than the solar year. Ramadan therefore moves back through the seasons by roughly 11 days each year, completing the full cycle in about three decades.
How long is a Hijri year?
A Hijri year has 354 days, or 355 in a leap year. The 12 months alternate between 30 and 29 days, and in a leap year Dhul Hijjah, the last month, has 30 days instead of 29.
Which calendar does the converter use?
The islamic-civil calendar, the standard calculated (tabular) Islamic calendar built into browsers, with the month names shown in English. It does not use the Umm al-Qura calendar, which can give a date one day different.
Why do different countries sometimes celebrate Eid on different days?
Because each country or community relies on its own moon sighting, or adopts its own calculated calendar, the new month — and with it Eid — can begin a day apart between places.