Find out exactly how old you are — down to the day and hour. Enter your birthdate and discover your precise age. Free on...
Ever wondered exactly how old you are — not just in years, but down to the exact day, hour, and minute? Our age calculator provides a comprehensive breakdown of your age from your birthdate to any target date (defaulting to today). It accounts for leap years, varying month lengths, and daylight saving time changes to provide the most accurate calculation possible. Whether you're filling out forms, planning a milestone birthday party, or just curious about your exact age, this tool gives you the precise numbers instantly.
Very accurate. We account for leap years and exact month lengths in all calculations.
Yes, enter any future date to see how old you will be on that day.
Calculations use the date only. For hour-level precision, results are approximate based on your local time.
No. Your birthdate is never stored or sent anywhere. All calculations happen in your browser.
"How old are you?" sounds like the simplest question in the world, yet computing an exact age — years, months, and days — involves calendar quirks that trip up even experienced programmers: months of different lengths, leap years, and even different cultural definitions of age itself. Here's what happens under the hood of this calculator, and why precise age matters more often than you'd think.
Exact age can't be computed by dividing elapsed days by 365, because years vary in length. The correct approach counts complete calendar years first, then complete months, then leftover days. Example: born 15 March 1990, calculating on 2 July 2026 → 36 full years (15 March 2026 has passed), then 3 full months (15 April, 15 May, 15 June), then the days from 15 June to 2 July = 17 days. Result: 36 years, 3 months, 17 days. The subtle rule: when the current day-of-month is smaller than the birth day-of-month, you "borrow" the length of the previous month — which is why the days component depends on whether that month had 28, 30, or 31 days.
A year is a leap year if divisible by 4, except century years, which must be divisible by 400 — so 2024 was a leap year, 1900 was not, and 2000 was. This keeps the calendar aligned with Earth's actual 365.2422-day orbit. About one person in 1,461 is born on February 29 and has a real answer to "when is your birthday in a common year?": most legal systems treat March 1 as the anniversary for age-of-majority purposes (some, like New Zealand, specify February 28). This calculator handles leap-day birthdays consistently, so a leapling's age still ticks over exactly once per year.
The system used here — you are 0 at birth and gain a year each birthday — is called international age, but it isn't universal. In the traditional East Asian reckoning, a baby is 1 at birth and everyone gains a year together at New Year; a child born in late December could be "2 years old" within weeks. South Korea, the last country using this system officially, standardized on international age by law in June 2023, instantly making most Koreans one or two years "younger" on paper. In horse racing and some school-entry systems, similar convention differences persist — a reminder that "age" is a definition, not just a measurement.
A 30-year-old has lived roughly 10,957 days, about 262,980 hours, and — at an average 70 beats per minute — has clocked over a billion heartbeats. Shared-birthday odds are higher than intuition suggests: in a group of just 23 people, there's a 50% chance two share a birthday, reaching 99.9% by 70 people. And because months differ in length, the interval between successive monthly "birthdays" varies from 28 to 31 days — which is why month-precise age can shift by a day even when the date arithmetic is flawless.