Islamic Date Converter (Hijri Calendar)

The Hijri calendar dates every Islamic observance, and it is the reason those observances move through the year: it is a lunar calendar roughly eleven days shorter than the solar one, so Ramadan, Hajj and both Eids drift earlier against the Gregorian calendar each year. This converter moves a date either way — Gregorian to Hijri and back. The sections below explain how the calendar is defined, why the converter can legitimately differ from your local mosque by a day, and which dates in the year carry obligations and are worth putting in a calendar now.

How the Hijri calendar is defined

Why Ramadan moves roughly eleven days earlier every year

A lunar year of 354 days against a solar year of about 365.24 days leaves a gap of roughly eleven days, and because the calendar has no mechanism to absorb it, every Hijri date advances by about that much against the Gregorian year. Over roughly 33 solar years the whole cycle completes, which is why a person can fast Ramadan in mid-winter and again, decades later, in high summer. Two practical notes follow: a fixed Gregorian date for Ramadan is always wrong, and the fasting calendar should be re-read each year rather than reused.

Arithmetic calendars, sighting, and why the answer can differ by one day

This converter uses an arithmetic (tabular) calendar. Its result is deterministic and correct as arithmetic — but Islamic months in practice begin with the sighting of the new crescent, which is a physical observation and can fall a day either side of the arithmetic prediction, and different countries start the month on different days. Two calendars resolve this in the public record:

• • The Umm al-Qura calendar — the official civil calendar of Saudi Arabia, published by ummulqura.org.sa. Use it when a document, a visa or a Saudi institution requires a Hijri date.
• • Local moon sighting — what determines the start of Ramadan, Shawwal and Dhul Hijjah where you live. Verified lunar phase data is published by NASA's Moon pages, useful for understanding why a predicted date and an announced date can disagree.

The four sacred months

The Quran names four months as sacred (9:36). They matter for planning because Hajj and the two Eids all fall around them:

AH, CE, and reading a converted date correctly

AH stands for Anno Hegirae, "in the year of the Hijra", and counts from 1 Muharram 1 AH — 16 July 622 CE. Where a converter shows a Hijri year it is the AH year; where it shows a Gregorian year it is CE. When a document quotes only a year without a month, remember that a Hijri year overlaps two Gregorian years, so "1447 AH" spans roughly mid-2025 to mid-2026.

Using the converter for real obligations

• • Fasting and Eid — convert the start of Ramadan and Shawwal, then use the Ramadan calendar for the day-by-day times.
• • Zakat — the hawl (lunar year) that determines when zakat on savings falls due is a Hijri year, so the payment date drifts earlier each Gregorian year. The zakat calculator takes the nisab; this page gives you the anniversary date.
• • Hajj — dates for the days of Hajj are Hijri; plan against the Hajj checklist.
• • Daily prayer — the five prayers run on solar time, not lunar; see the prayer times and qibla finder.

Sources: Umm al-Qura civil calendar (ummulqura.org.sa); NASA Moon (science.nasa.gov) for lunar phase data; Quran 9:36 and 2:185 (quran.com). The converter uses an arithmetic calendar — announced dates for religious observances may differ by one day.

The Twelve Islamic Months