The Hijri calendar is lunar-based with years of about 354 days, while the Gregorian calendar is solar-based with years of about 365 days. This roughly 11-day difference adds up over time, making your Hijri age about 3% higher than your Gregorian age.

To calculate your Hijri age, convert your Gregorian birthdate to Hijri, then count the lunar years elapsed. Since each Hijri year is shorter, you will be slightly "older" in Hijri years. This tool does the calculation automatically — just enter your birthdate.

The Hijri calendar is based on the lunar cycle — each month begins with the sighting of a new crescent moon. It was established during the caliphate of Umar ibn al-Khattab, with the epoch set at the Prophet Muhammad's migration (Hijra) from Mecca to Medina in 622 CE.

Your Hijri birthday falls on a different Gregorian date each year because the lunar calendar shifts about 10-11 days earlier annually. Use this calculator to enter your birthdate and it will show you the exact Gregorian date of your next Hijri birthday.