Age Calculator: Years, Months, Days & Full Time Breakdown
Calculate age from date of birth. Exact chronological age in years, months, days plus total weeks, hours, minutes, seconds. Leap years and leap-day birthdays handled. Next birthday countdown. Western age. Free, runs locally, no sign-up.
How to Calculate Age from Date of Birth
Exact chronological age is computed from the total days between your birth date and the "as of" date, then converted into years, remaining months, and days. Month lengths (28โ31 days) and leap years are applied automatically. The calculator's Information Hub (above) explains the exact formula, how we handle leap years and leap-day birthdays, and how we derive weeks, hours, minutes, and seconds.
Western vs. Korean and Other Age Systems
This calculator uses Western chronological age: 0 at birth, 1 on your first birthday. Korean age and some East Asian systems count from conception or increment on Lunar New Year, so the same dates can yield different ages. The Information Hub above summarizes how we apply the Western standard.
How to Use the Age Calculator
- Date of Birth:Enter your birth date. Use the date picker for easy month/year navigation.
- Age at the Date of:Defaults to today. Change it to find your age at a specific dateโa milestone birthday, retirement, or any point in time.
- Exact Chronological Age:Main result shows years, months, and days in bold. Below: total months, weeks, days, hours, minutes, secondsโall locale-formatted.
- Next Birthday:Time until your next birthday (e.g., "5 Months, 12 Days"). Leap-day birthdays use Feb 28 in non-leap years.
Age Calculator FAQ
How do I calculate my age from my date of birth?
Age is the years, months, and days between your birth date and the "as of" date. The calculator uses total days between the two dates, then applies month lengths and leap years to get an exact breakdown (including total weeks, hours, minutes, seconds). See the Information Hub in the calculator for the exact formula and rules.
Why does the second date default to today?
"Age at the Date of" defaults to today so you see your current age right away. Change it to any date to find your age at that momentโmilestone birthdays, retirement, or historical events.
How do leap years affect my age in days?
Leap years add Feb 29 every four years (except most century years). Each Feb 29 in your span is counted. Example: born Feb 28, measured Mar 1 in a leap year = 2 days; in a nonโleap year = 1 day.
I was born on February 29. How is my age calculated?
Standard legal practice: leap-day birthdays count as Feb 28 in non-leap years. In 2025 (non-leap), your birthday is Feb 28 for age purposes. The Next Birthday countdown uses the same rule.
What is Western age vs Korean age?
Western chronological age counts from birth: 0 on your birth day, 1 on your first birthday. Korean age (and some East Asian systems) often counts from conception or bumps everyone on Lunar New Year, so a baby can be "1" at birth. This calculator uses the Western standard.
Can I find my age at a future or past date?
Yes. Set "Age at the Date of" to any date for your exact age at that moment. Handy for retirement planning, "How old will I be in 2030?", or contractual age checks.