Enter your date of birth in either calendar. You get your exact age in Gregorian years, months and days, your exact age in Hijri years, months and days — genuinely larger, because a lunar year is about eleven days shorter — and the date of your next Hijri birthday.
Fill in the required fields to continue.
Fill in the fields above, then press the button. Nothing is sent anywhere — the calculation runs entirely in your browser.
Nothing saved yet. Dates you calculate are kept in this browser only.
The Umm al-Qura tables cover roughly 1300–1600 AH (about 1882–2174 CE). Outside that span browsers fall back to an arithmetic approximation, so dates beyond it are refused rather than shown.
A Gregorian year tracks the earth’s orbit and runs 365.2425 days. A Hijri year is twelve lunar months and runs about 354.37 days. That gap of roughly eleven days a year is why Ramadan moves through the seasons, and it is also why you are older when your life is counted in Hijri years: more short years fit into the same span of time. The two calendars gain a whole year on each other about every 32.5 Gregorian years.
The divergence is not a rounding error and it is not constant in absolute terms — it compounds with age. It is a couple of months in childhood, close to a full year by thirty, and about three years by a hundred.
Measured on the exact Gregorian anniversary of a birth, converted through the Umm al-Qura calendar:
As a rough guide, take your Gregorian age and add about one year for every 32.5 years you have lived. The calculator above does it exactly instead of approximating: it converts your date of birth to its Umm al-Qura Hijri date, converts today to its Hijri date, and counts the whole Hijri years, months and days between the two.
Because Hijri years are shorter. Twelve lunar months come to about 354 days against the solar year’s 365.24, so more of them fit into the same lifetime. Someone who is 36 Gregorian years old is about 37 Hijri years old, and the gap keeps widening by roughly eleven days every year.
It is the same Hijri day and month you were born on, occurring in the current Hijri year. Because the Hijri year is about eleven days shorter, that date falls roughly eleven days earlier in the Gregorian calendar each year, so your Hijri and Gregorian birthdays only land on the same day about once every 33 years.
Enter it in the Gregorian field above and the Hijri date appears immediately, along with the name of the Hijri month you were born in. If you only want a date converted, with no age arithmetic, the Hijri date converter does the same job in both directions.
It is exact for the Umm al-Qura calendar, which is computed in advance rather than observed. It is not necessarily the date your own family or community recorded: many follow local moon sighting, which can place the start of a month a day either side of the calculated date. So a Hijri date of birth from this tool is accurate to within about a day, and a Hijri birthday should be treated as approximate.
For a single date conversion with no age arithmetic, use the Hijri date converter. To see which observances fall in a given Hijri month, see the Islamic days calendar.