Easily calculate exact date differences between any two Hijri dates, convert lunar durations to solar years, compute your Islamic age, and track countdowns to Ramadan and Eid with RiazHub.com’s browser-based Islamic Date Calculator.
▶ Start Date
⏹ End Date
➕ Base Hijri Date & Calculation Setup
🕌 Select Major Islamic Event
⏳ Enter Date of Birth & Target Date
1. Islamic Lunar Year vs. Solar Gregorian Year: The Islamic (Hijri) calendar is purely lunar and based on 12 synodic lunar months (29.530588 days each). A Hijri year lasts approximately 354.36 days, making it roughly 10.88 to 11 days shorter than the solar Gregorian year (365.2425 days).
2. Annual Date Shift: Because of this ~11-day difference, Islamic months and events (such as Ramadan and Eid) rotate backwards through all four seasons over a 33-year solar cycle.
3. Islamic Age vs. Gregorian Age: A person accumulates approximately 1 extra Hijri lunar year for every 33 Gregorian solar years lived. For example, a person who is 33 in solar years is approximately 34 in Islamic Hijri years.
4. Umm al-Qura & Moon Sighting Adjustments: This calculator uses the official Saudi astronomical Umm al-Qura calendar via the browser's native Internationalization API (`Intl.DateTimeFormat`), backed by Julian Day Number algorithms. Use the Moon Sighting Offset selector above (-2 to +2 days) to match regional crescent sighting announcements in your area.