How to calculate exact age
- Enter the date of birth.
- Leave age on date as today, or change it to any past or future date.
- Press Calculate to see the age in years, months and days, the total days lived, the weekday of birth and the next birthday.
When an exact age matters
- Eligibility cutoffs. School enrollment, sports age groups, retirement plans and Medicare rules use exact ages on a set date.
- Family history. Genealogists compare an age written on a census or death record with a birth date to check that both refer to the same person.
- Milestones. Many people celebrate a 10,000th day or a half birthday. The total-days figure shows when those come up.
Why months and days can surprise you
Months have 28 to 31 days, so "one month later" does not always mean the same number of days. The calculator counts complete calendar months, the way people normally say an age. Someone born on January 31 completes a month on the last day of February. A person born on February 29 has a birthday on February 28 in common years for this count.
Related calendars and guides
Open any year calendar from 1995 to 2027 to see the date in context with US federal holidays, observances, moon phases and the events of that year. The calendar guides explain the rules behind every result.