Age Calculator

The calculator counts whole years first, then whole months, then remaining days, exactly as a person would: from 15 March 1990 to 3 September 2026 is 36 years, 5 months and 19 days. Hours and minutes come from the current time of day. It uses the calendar rather than dividing by 365.25, so a birthday on 29 February is handled correctly (the year turns over on 1 March in non-leap years), and the difference in month lengths does not accumulate into an error over decades.

The result also shows the total number of days you have been alive and the countdown to your next birthday, which is the same calculation the birthday countdown runs continuously.

Ask three tools how old someone born on 31 January is on 1 March and you may get three answers, because "one month" from 31 January does not exist in February. Conventions differ: some count 1 month and 1 day, some 29 days. Days-in-month, leap years and time zones all create these edge cases. This calculator follows the common convention used by most official forms: complete calendar months, with the remainder counted in days from the same day-of-month in the previous month. For legal purposes, such as eligibility "on or after the 18th birthday", what matters is the date itself, not the fractional age, and this page shows both.

Below the main result you can see your age in total months, weeks, days, hours and minutes. Some milestones are easier to spot this way: your 10,000th day falls a little after your 27th birthday, and your billionth second arrives at 31 years and about 8 months. To calculate someone's age on a past or future date, for example on the day of an exam or a wedding, change the "age at" date. To find the gap between any two dates that are not birthdays, the date calculator does the same arithmetic without the birthday framing.

• Western counting. Age increases on the anniversary of birth. A baby is 0 until its first birthday.
• Korean traditional age counted a person as 1 at birth and added a year every 1 January, so everyone was one or two years older than in the Western system. South Korea standardised on international age in June 2023.
• East Asian lunar reckoning in some communities still adds a year at Lunar New Year rather than on the birthday.
• Official documents almost everywhere use the Western convention, which is what this calculator returns.