Age Calculator
How old are you, exactly? Enter a date of birth and any “as of” date to get a precise age in years, months and days — plus totals in weeks, days and hours, and a countdown to the next birthday.
Exact age is calculated the way you would subtract dates by hand: years first, then months, then days. When the day of the “as of” date is earlier in the month than the birthday, the calculator borrows a month — using the real number of days in the previous month, so February and 31-day months are handled correctly.
Totals in weeks, days and hours count every calendar day between the two dates, including leap days. The birthday countdown finds the next occurrence of the birth month and day and counts the days remaining.
Worked examples
Everyday age
Born June 15, 1990, measured on September 17, 2026: 36 years, 3 months and 2 days.
→ 36y 3m 2d
Total days alive
Someone born January 1, 2000 has lived 9,500+ days by late 2025 — leap days included.
→ Counted automatically
Half-birthday planning
Set the “as of” date six months ahead to find the exact day a child turns 7½.
→ Works for any date