Hijri–Gregorian Date Converter
Choose a direction, enter a Gregorian or Hijri date, and see the matching civil date. Results use the common tabular (arithmetic) Islamic calendar — handy for planning, with a note that moon-sighting calendars can differ by a day.
Calculate
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Result
The formula
Both calendars map onto a Julian day number. Gregorian dates use the proleptic civil rules after 1582; Hijri dates use the Kuwaiti/tabular arithmetic calendar (30-year cycle with 11 leap years). Converting either way is Julian-day arithmetic, then formatting with month names.
Worked example
- Gregorian 1 March 2025
- Tabular conversion → 1 Ramadan 1446 AH
- Converting that Hijri date back returns 1 March 2025
Result: 1 Ramadan 1446 AH ↔ 1 March 2025
How Hijri–Gregorian conversion works
Islamic dates in everyday apps usually follow either moon sighting (regional announcements) or a fixed arithmetic table. This calculator uses the widely published tabular method so results are reproducible everywhere.
Tabular (arithmetic) Hijri
Months alternate 30 and 29 days in a 30-year cycle with 11 leap years, when Dhu al-Hijjah gains a 30th day. The epoch aligns with the civil Islamic calendar used in many converters and libraries (often called the Kuwaiti algorithm).
Why results can differ from a mosque calendar
Authorities that announce Ramadan or Eid by crescent sighting may be one day earlier or later than the table. Saudi Umm al-Qura and other official schedules also apply their own tweaks. Treat this page as a civil planning aid; follow your local announcement for worship.
Gregorian civil dates
Inputs are Gregorian calendar dates without time of day. Historical dates before the 1582 reform use the algorithm’s Julian-era branch; everyday modern dates use the standard Gregorian leap rules.
What we do not claim
We do not replace an official moon-sighting circular, Umm al-Qura publications, or a printed Hijri diary from your community. When those disagree with the table, prefer the authority you follow for fasting and festivals.
Interesting facts
About 11 days shorter
A Hijri year is roughly 354 or 355 days, so Islamic dates drift through the seasons — Ramadan cycles around the Gregorian year over ~33 years.
Twelve named months
Muharram starts the year; Ramadan is the ninth month; Dhu al-Hijjah is the twelfth and hosts the Hajj dates in the first half of the month.
AH numbering
Hijri years are often written with AH (Anno Hegirae), counting from the Hijra. Year 1 AH corresponds to 622 CE in the tabular epoch.
Leap pattern
In the 30-year tabular cycle, 11 years are leap years. That keeps the average month length close to the lunar synodic month.
Pairs with prayer tools
Once you know a Hijri festival date in Gregorian form, prayer-time and qibla tools help with the day’s worship logistics.
Frequently asked questions
Select Gregorian → Hijri, enter the civil date, and read the Hijri day, month name, and year (AH). The reverse mode converts Hijri back to Gregorian.
Sighting-based and some official calendars can shift by ±1 day from the arithmetic table. Use local announcements for fasting and Eid; use this converter for civil planning.
No. Umm al-Qura is Saudi Arabia’s official civil Hijri calendar and sometimes differs slightly. This tool uses the common tabular Kuwaiti-style algorithm found in many open converters.
Anno Hegirae — the year count of the Islamic calendar starting from the Hijra. Example: 1447 AH.
Yes. Enter 1 Ramadan or 1 Shawwal (Eid al-Fitr) in Hijri → Gregorian mode, or convert a Gregorian date to see the Hijri month. Confirm festivals with your local authority.
No. Only calendar dates are converted. The civil day boundary still depends on local midnight or Maghrib conventions when people speak casually about “tonight’s date.”
References
- Islamic calendar Overview of lunar months, AH reckoning, and civil versus observational practice.
- Calendar — Islamic civil (tabular) calendar Documents algorithmic Islamic (civil) calendars used in software date conversion.