How the age is counted
Age is counted the way people and most official forms count it: first the whole years, then the whole months, then the days left over. Each month is counted from the same day of the month as the birthday, so someone born on 15 May 1990 is 36 years, 4 months and 24 days old on 9 October 2026. If the birth day does not exist in a shorter month, the month is counted to that month's last day: from 31 January, one month is complete on 28 February (or 29 February in a leap year). The total days are the exact number of calendar days between the two dates, so they never depend on how long each month is.
Birthdays on 29 February
If you were born on 29 February, your birthday only appears on the calendar every four years. This calculator treats 28 February as your birthday in common years, so a year of age is complete on 28 February and the next-birthday countdown points to that date. Some countries and organisations use 1 March instead. If a form needs the exact rule, check with the authority that issued it; the difference is never more than one day.
Why your Hijri age is higher
The Hijri calendar is lunar. Its year has 354 or 355 days, about 11 days shorter than a Gregorian year, so Hijri birthdays come round a little earlier each year and your Hijri age gains roughly one year for every 33 Gregorian years. Someone who is 36 by the Gregorian calendar is usually 37 in Hijri years. The calculator converts both dates with the Umm al-Qura calendar, the official calendar of Saudi Arabia, and counts the completed Hijri years between them. Official dates in some countries depend on a local moon sighting, so a Hijri date here can be a day away from the one on a certificate.
Age on a specific date
Many forms ask for your age on a particular day rather than today: school admissions with an age cut-off date, university or job applications, insurance quotes, sports age groups, or retirement and end-of-service planning. Change the "Age on this date" field to that day and the result updates at once. The date can be in the past or the future, so you can also see exactly when a child reaches a certain age.
Private by design
Your date of birth is personal data, so the calculation runs entirely in your browser. Nothing you type is sent to our servers or stored, and the page keeps working if you lose your connection after it has loaded. We only count anonymous events, such as that the calculator was used, to learn which tools people need.