Hijri-Gregorian Islamic Date Converter Online Free
Move dates in both directions between the Gregorian calendar and the Islamic Hijri calendar using the tabular (arithmetic) algorithm, with full month names in English and Arabic, automatic leap-year handling for Dhu al-Hijjah, day-of-week confirmation, and a moon-sighting adjustment slider from −2 to +2 days so you can match your local committee’s announcements.
Hijri-Gregorian Islamic Date Converter In-Browser Workspace
Input data or select files to begin. 100% private, client-side execution with zero server transmission.
How to Use Hijri-Gregorian Islamic Date Converter
- Step 1: Choose Gregorian → Hijri or Hijri → Gregorian with the mode buttons.
- Step 2: For Gregorian → Hijri, pick any date; for Hijri → Gregorian, enter year, month (1–12), and day with built-in month-length validation.
- Step 3: Optionally move the Moon-Sighting Adjustment slider (default 0, range −2 to +2) to align with local crescent sighting reports.
- Step 4: Click Convert Date to see the paired dates, Arabic script, month metadata, weekday, and round-trip check.
- Step 5: Reference the 12-month list at the bottom for sacred months, Ramadan, Eid, and Hajj markers.
About Hijri-Gregorian Islamic Date Converter
The Hijri calendar is lunisolar: months alternate 30 and 29 days (odd months long, even short), so a year is 354 or 355 days — roughly 11 shorter than a Gregorian year, which is why Islamic holidays drift about 11 days earlier each solar year. This converter uses the tabular Islamic algorithm (closely related to the classic Kuwaiti algorithm): a Gregorian date is first converted to a Julian Day Number via the Fliegel–Van Flandern formula, then the inverse Kuwaiti steps recover Hijri year, month, and day. The reverse path applies the closed-form JDN = ⌊(11·hy + 3)/30⌋ + 354·hy + 30·hm − ⌊(hm − 1)/2⌋ + hd + epoch before the standard JDN→Gregorian expansion. Leap years in the tabular cycle follow ((11·y + 14) mod 30) < 11, giving Dhu al-Hijjah a 30th day in leap years — the validator rejects day 30 in non-leap years with an explicit message. Because actual months begin on the observed new moon rather than the arithmetic table, governments and religious bodies can differ by one or two days; the ±2-day adjustment slider shifts the JDN before conversion so you can reproduce a committee’s published date. The tool also echoes a round-trip (Gregorian → Hijri → Gregorian) result so you can verify the pair immediately. All twelve month names and Arabic labels come from the shared hijri-adjust config, keeping sacred-month flags consistent with other Islamic date features in the toolkit.
Frequently Asked Questions
Why does my mosque announce a date one day different from this tool?
Local moon sighting (rukyat-e-hilal) can advance or delay the month by 1–2 days versus the arithmetic table. Use the adjustment slider to match your country’s official announcement — that is exactly what the ±2 range is for.
Is the tabular algorithm the same as Saudi Arabia’s Umm al-Qura calendar?
Not exactly. Umm al-Qura uses astronomical criteria with planned adjustments; the tabular method is pure arithmetic. For civil planning either is acceptable with the sighting slider; for legal Hajj dates always defer to official declarations.
How are leap years determined?
Tabular leap years satisfy ((11·year + 14) mod 30) < 11, producing about 11 leap years every 30. Dhu al-Hijjah then has 30 days instead of 29, and the day-30 validator enables automatically.
Can I convert dates before 622 CE?
The math will return a year number, but the Hijri calendar did not exist before its epoch, so results before 1 AH are not historically meaningful. Valid practical range starts around July 622 CE.
Does converting send my dates to a server?
No. All JDN arithmetic runs in-browser; nothing about the dates you convert is logged or transmitted.