Islamic Calendar is based on the Astronomical Crescent Moon each month

📅 Timeline of Hijri and Calendar Alignment

Event Hijri Date Julian Calendar Gregorian Equivalent
Start of Year 1 AH (Muharram 1) 1 Muharram 1 AH 16 July 622 CE 19 July 622 CE
Prophet ﷺ leaves Makkah End of Safar 1 AH ~9 September 622 CE ~12 September 622 CE
Stay in Cave of Thawr 1–3 Rabiʿ al-Awwal 1 AH ~12–14 September 622 CE ~15–17 September 622 CE
Arrival at Quba 8 Rabiʿ al-Awwal 1 AH 23 September 622 CE 26 September 622 CE
Friday Jumuʿah at Banū Sālim
ibn ʿAwf & entry into Madinah		 12 Rabiʿ al-Awwal 1 AH 27 September 622 CE 30 September 622 CE

Crescent moon is visible 24 hours after new moon, please follow local Moon Sighting Committee

New Moon Calculator – UTC Date, Time & JDN by Formula

Algorithm: Jean Meeus Astronomical Algorithms, Ch.49 — fully computed, no hardcoded times. Accuracy: ±2 minutes.
Dates before 15 Oct 1582 are shown in the Julian calendar; from 15 Oct 1582 onward in the Gregorian calendar.

Gregorian / Julian Year:  

# Month Lunation (k) UTC Date & Time Calendar Day JDN (fractional) Hijri Month Hijri Year

JDN = Julian Day Number (noon epoch, UT)
— Delta-T estimated per Meeus polynomial for each era
— Weekday computed via Zeller / JDN mod-7 (works for any date, any calendar)
— Hijri year derived astronomically: lunation count since 1 Muharram 1 AH (JD 1948439.0, new moon of 16 Jul 622 CE Julian / 19 Jul 622 Gregorian)
— Julian calendar used for dates before 15 Oct 1582 (JD 2299161).