Quick Answer
Hijri (Islamic lunar) dates are converted from Gregorian dates using astronomical or arithmetic calculation methods that account for the roughly 354-355 day Islamic lunar year, which is about 10-11 days shorter than the 365-day Gregorian solar year.
What Is Hijri Converter?
The Hijri calendar is the lunar calendar used in Islam, beginning from the Hijra (Prophet Muhammad's migration from Mecca to Medina in 622 CE). Unlike the Gregorian calendar, which is solar-based (365 or 366 days per year), the Hijri calendar is purely lunar, with each month beginning at the sighting (or astronomical calculation) of the new crescent moon, resulting in a year of approximately 354-355 days.
Because the Hijri year is about 10-11 days shorter than the Gregorian year, Hijri dates shift earlier relative to the Gregorian calendar each year, Islamic months and observances like Ramadan move through all four Gregorian seasons over roughly a 33-year cycle, rather than falling at a fixed time of year.
Hijri date converters use either astronomical calculation (predicting the moon's position mathematically) or tabular/arithmetic methods (a fixed pattern approximating the lunar cycle), the exact date can occasionally differ by a day depending on the method and local moon-sighting practices, especially for the start of Ramadan and Eid.
How to Use
- 1Enter the Gregorian date you want to convert.
- 2The calculator returns the equivalent Hijri date.
- 3You can also convert in the reverse direction, enter a Hijri date to find its Gregorian equivalent.
Formula
Based on astronomical lunar calculation or a standardized tabular Hijri calendar algorithmNot a simple linear formula, accounts for the ~354.367-day average lunar year length
Example: Converting a Gregorian date to Hijri
- Gregorian date entered: June 21, 2026
- Calculator applies lunar calendar conversion algorithm
Tips & Things to Know
- Hijri dates for religious observances (start of Ramadan, Eid) can vary by a day between countries or organizations due to differing reliance on physical moon sighting versus astronomical calculation, local mosque or national announcements take precedence for religious practice.
- Because the Hijri year is shorter, a person's 'Hijri age' in years will be a slightly higher number than their Gregorian age at the same point in life, since more Hijri years fit into the same span of time.
- Hijri calendar converters are useful for general reference and planning, but for precise religious determinations (exact start of Ramadan, Hajj dates), follow official announcements from recognized Islamic authorities in your region.
- The Hijri calendar has 12 months like the Gregorian calendar, but all are 29 or 30 days (no months with 31 days), contributing to the shorter overall year length.