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Hijri Calendar Converter

Use this free Hijri calendar converter to change any Gregorian date into its Hijri date, or any Hijri date into its Gregorian date. It also shows today's Hijri date at the top of the page. The converter uses the tabular Islamic calendar, the standard arithmetic version of the Hijri calendar, so you can plan ahead for Ramadan, Eid, Hajj, and other Islamic dates with confidence.

How it works

The Hijri calendar is a lunar calendar: each month begins with the new moon, and a full cycle of 12 months takes about 354.37 days. Because that is about 11 days shorter than the solar year of 365.25 days, Hijri dates drift earlier through the Gregorian calendar by roughly 11 days each year. Ramadan, for example, falls in a different season every decade or so, and over about 33 years it works its way through all four seasons.

This converter uses the tabular Islamic calendar, also called the Kuwaiti algorithm. It is a fixed arithmetic system, which means the same input always gives the same output, unlike moon sighting, which depends on weather and location. The system counts days from the Islamic epoch, 16 July 622 CE in the Julian calendar, which is Julian Day 1948439.5. Every date, Gregorian or Hijri, is first turned into a Julian Day Number, a simple count of days, and then converted back into the other calendar.

The months follow a fixed pattern. Odd-numbered months — Muharram, Rabiʿ al-awwal, Jumada al-ula, Rajab, Ramadan, and Dhu al-Qaʿdah — have 30 days. Even-numbered months — Safar, Rabiʿ al-thani, Jumada al-akhirah, Shaʿban, Shawwal, and Dhu al-Hijjah — have 29 days. That pattern alone gives 354 days. The extra day in a leap year goes to Dhu al-Hijjah, the twelfth month, which then has 30 days instead of 29.

Leap years keep the calendar in step with the real moon. In each 30-year cycle, the leap years are years 2, 5, 7, 10, 13, 16, 18, 21, 24, 26, and 29 — eleven leap years per cycle. That makes the average Hijri year 354 days plus 11/30 of a day, or about 354.367 days, which matches the true average lunar year to within a fraction of a day per century. The calculator checks whether your Hijri year is a leap year and adjusts Dhu al-Hijjah accordingly, so dates in that month convert correctly.

The twelve Hijri months

Worked example

Take 1 January 2026 and convert it to the Hijri date.

Step 1: Turn the Gregorian date into a Julian Day Number. For 1 January 2026, the count is 2461041.5.
Step 2: Subtract the Islamic epoch, 1948439.5, leaving 512602 days since the start of the Hijri calendar.
Step 3: Divide those days into 30-year cycles and leap years to find the year. The result is the year 1447.
Step 4: Work through the months of 1447 — Muharram has 30 days, Safar 29, and so on — until the remaining days land in the seventh month, Rajab, on day 12.

The answer is 12 Rajab 1447 AH, a Thursday. Enter 1 January 2026 in the converter and it gives exactly that. Going the other way, 1 Ramadan 1447 converts to 18 February 2026 on the tabular calendar.

Tabular calendar vs. moon sighting

The tabular calendar is exact and predictable, which is why it is used in software, printed calendars, and official civil calendars in several countries. But the traditional Islamic month begins when the crescent moon is sighted, and that sighting can fall a day earlier or later than the arithmetic date. Clouds, the observer's location, and different rulings about whether a sighting in one country applies to another can all move the date by a day. For everyday planning — knowing roughly when Ramadan or Eid will fall — the tabular date is fine. For fasting, prayer, and festival days, confirm with your local mosque or religious authority, which announces the month after the sighting.

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