Calculate your exact age in years, months, and days from any date of birth, plus a live countdown to your next birthday and your total age in weeks, days, hours, minutes, and seconds.
Most everyday answers to 'how old are you' round down to a single number of completed years, which is accurate but leaves out useful detail — like how many months and days have passed since your last birthday. Exact age fills in that detail, expressing your age as a full years/months/days breakdown calculated directly from the calendar, the same way you'd count it by hand: full years elapsed, then full months elapsed since your last birthday, then the remaining days. This is the standard, unambiguous way age is defined in most legal, medical, and administrative contexts whenever more precision than 'just the year' is required.
The calculation walks forward from your date of birth to today using the same logic as counting on a physical calendar. It first finds the difference in years between the two dates, then the difference in months, then the difference in days-of-month. If the day-of-month difference comes out negative — meaning today's date-of-month is earlier in the month than your birth date-of-month — it borrows a month, converting that borrowed month into however many days it actually has (28, 29, 30, or 31, depending on the specific month and whether it's a leap year), and adds that to the day count. If the month difference is then negative, it borrows a year in the same way. This calendar-walking approach is what makes the result exact rather than an averaged estimate, correctly handling every month-length and leap-year edge case along the way.
The countdown finds the next occurrence of your birth month and day starting from today: if your birthday hasn't happened yet this calendar year, the countdown targets this year's occurrence; if it already has, it targets next year's. For someone born on February 29, the tool substitutes February 28 in any year that isn't a leap year, since February 29 simply doesn't exist most years — this is the same convention used by most systems and calendars for handling leap-day dates. Once the target date is set, the countdown is just the precise time difference between now and that date, broken into days, hours, minutes, and seconds and refreshed once per second so it's always showing the current, live remaining time.
Beyond the years/months/days breakdown, this tool also shows your total age measured in several other units — weeks, days, hours, minutes, and seconds — all computed as the exact elapsed time since your date of birth (at midnight, local time) until the current moment. These figures update live once per second, since the seconds and minutes counts are constantly increasing. They're mostly a fun way to see your age from a different angle — most people don't think in terms of 'I am 315 million seconds old,' but the number is exact and can be a genuinely striking way to visualize just how much time has actually passed since a particular date.
Exact, calendar-accurate age comes up more often than it might seem: school enrollment and grade-placement cutoffs frequently depend on a child's exact age (down to the month or day) as of a specific cutoff date, not just their birth year; certain age-restricted eligibility rules require confirming someone has reached an exact age threshold, not just 'turned that age sometime this year'; forms for insurance, medical records, or government services sometimes explicitly ask for age in years and months; and anyone counting down to a milestone birthday wants an accurate, live countdown rather than a rough mental estimate. In each of these cases, a simple 'current year minus birth year' subtraction can be off by one depending on whether the birthday has already happened this year — the calendar-based calculation this tool performs avoids that ambiguity entirely.
Age Calculator handles one specific kind of date math. These related calculators cover other everyday date and number calculations.