Age Calculator
Work out an exact age in years, months and days on any date — plus decimal age, total months, weeks, days and hours lived, the countdown to the next birthday, the weekday you were born and upcoming day-count milestones.
How it works
age = whole calendar years from the birth date, then whole months, then leftover days · decimal age = years + days since last birthday ÷ days in that birthday year
The calculator walks the real calendar instead of dividing by 365.25: it counts how many whole years fit from the birth date to the “age on” date, then whole months from that anniversary, then the days that remain. That is why someone born June 15 always turns a round number of years exactly on June 15, however many leap years passed in between. Total days lived is an exact calendar-day count; weeks, hours, minutes and seconds come from it. The “age on” date defaults to today but can be any date, so the same tool gives an age at a past event, at death, or on a future date. People born on February 29 can choose whether their birthday falls on February 28 or March 1 in common years. The tables list the next five birthdays with their weekdays and upcoming milestones such as 10,000 days, 1,000 weeks or 1 billion seconds.
Worked example
Born June 15, 1995 and checked on September 11, 2026: 31 whole years reach June 15, 2026, two more months reach August 15, and 27 days remain — 31 years, 2 months, 27 days, or 31.24 in decimal years (88 of the 365 days to the next birthday have passed). That is exactly 11,411 days lived: 1,630 weeks and 1 day, or about 273,864 hours. The 32nd birthday is Tuesday, June 15, 2027, 277 days away, and the next milestone is 1 billion seconds old on February 21, 2027.
Frequently asked questions
Why do different sites give a different months-and-days age?
Month lengths vary, so tools must choose a convention when borrowing days from a partial month. This calculator uses the standard one — walk whole years, then whole months, then count leftover days — while some tools approximate with fixed 30-day months and drift by a day or two.
How is a February 29 birthday handled?
By default the birthday is February 28 in common years, so the age still ticks over once a year. Some jurisdictions use March 1 instead — pick that rule under More options. Either way the difference is a single day.
Can I find someone’s age on a past or future date?
Yes. Change “Age on this date” to any date after the birth date — for example a date of death, a wedding day or a future retirement date — and every figure is worked out for that date.
Is the total days lived exact?
Yes — it is a true calendar count that includes every leap day. Shortcuts that multiply years by 365 lose roughly one day for every four years lived. The hours, minutes and seconds assume midnight-to-midnight days, so they ignore your time of birth.
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This calculator is for educational purposes. Double-check important results before acting on them.