Hijri Date Converter

About this calculator

This converter translates any date between the Islamic (Hijri) calendar and the Gregorian calendar, in either direction. The Hijri calendar is purely lunar: each of its twelve months — Muharram through Dhu al-Hijjah — begins with a new crescent moon, so a Hijri year runs about 354 days, roughly 11 days shorter than the 365-day solar Gregorian year. Because of that gap, Islamic dates such as Ramadan, Eid, and the Hajj shift about 11 days earlier each Gregorian year and cycle through all four seasons over roughly 33 years. Pick a direction, type a year, month, and day, and read the converted date together with its day of the week. By default it shows today’s date converted to Hijri, so it doubles as a "what is the Hijri date today" lookup.

How to read your results

The toggle at the top chooses the direction: "Gregorian → Hijri" turns a civil date (for example a birthday or a document date) into its Islamic equivalent, and "Hijri → Gregorian" does the reverse. The headline result is the converted date — its year, named month, and day in the target calendar — followed by the day of the week, which is the same real weekday for both calendars because they describe the same 24-hour civil day. Hijri years are written with the suffix AH (Anno Hegirae, "in the year of the Hijra"), counting from Prophet Muhammad’s migration to Medina in 622 CE. The note under the result is important: this tool uses the tabular (arithmetic) Hijri calendar, which can land one or two days away from a date set by actual moon-sighting or by the Saudi Umm al-Qura calendar.

How it's calculated

Both directions pivot on the Julian Day Number (JDN), a continuous integer count of days that is independent of any calendar. To convert, the input date is first reduced to its JDN, then that JDN is read out in the target calendar. The Gregorian side uses the standard civil-date formula; the Hijri side uses the tabular (arithmetic) Islamic algorithm from the US Naval Observatory and Fourmilab — a 30-year cycle in which the years where ((year × 11) + 14) mod 30 is less than 11 are leap years — anchored to the epoch JDN 1948439.5 (1 Muharram AH 1 = Friday 16 July 622 CE in the Julian calendar). The day of the week is derived directly from the JDN, so it is identical for the two calendars. The drift between the calendars is quantified by comparing the mean tabular Hijri year (10631 ÷ 30 ≈ 354.37 days) with the mean Gregorian year (365.2425 days), a deficit of about 10.9 days per year. "Today" is computed at local civil midnight in your time zone after the page loads, so the default date is correct wherever you are without baking a build-time date into the page.

Worked example

Convert 1 Muharram 1446 AH (Hijri → Gregorian).

The tabular Islamic New Year 1 Muharram 1446 AH falls on Monday, 8 July 2024 CE. Many countries that follow moon-sighting or the Umm al-Qura calendar began 1446 on 7 July 2024 instead — exactly the ±1 day tabular-versus-sighting difference this tool discloses. Converting the other way, 1 January 2000 CE comes out as 24 Ramadan 1420 AH.

Frequently asked questions

Why does my Islamic (Hijri) birthday move about 11 days earlier each year?

The Hijri year is lunar — twelve lunar months totalling about 354 days — while the Gregorian year is solar at about 365 days. That 11-day shortfall means a fixed Hijri date drifts roughly 11 days earlier on the Gregorian calendar every year, and over about 33 years it travels through all four seasons before lining up again.

Tabular vs moon-sighting (Umm al-Qura) — why might this differ by a day or two?

This converter uses the tabular (arithmetic) Islamic calendar, which fixes month lengths by a 30-year cycle with 11 leap years, so every date is fully deterministic. Moon-sighting calendars and the Saudi Umm al-Qura calendar instead depend on whether the new crescent is actually seen, which can fall one day — occasionally two — before or after the arithmetic date. Treat the tabular result as an exact calculated reference, not a religious moon-sighting ruling.

How many days are in a Hijri year?

A common Hijri year has 354 days and a leap year has 355, alternating 30-day and 29-day months (the twelfth month, Dhu al-Hijjah, gains a day in a leap year). In the tabular calendar, 11 of every 30 years are leap years, giving a long-run average of about 354.37 days per year.

Is this the official date for Ramadan, Eid, or Hajj?

No. Religious observances such as Ramadan, Eid al-Fitr, Eid al-Adha, and the Hajj are commonly set by local moon-sighting or by a national authority (in Saudi Arabia, the Umm al-Qura calendar), which can differ from this arithmetic date by a day or two. Use this tool for planning, genealogy, and document conversion — and confirm religious dates with your local authority.

Sources

• aa.usno.navy.mil/faq/islamic
• www.fourmilab.ch/documents/calendar
• en.wikipedia.org/wiki/Tabular_Islamic_calendar

Reviewed by the YouCalc Team · Last reviewedJune 13, 2026