Age Calculator
Press Calculate to see the results.
This age calculator finds the exact time between a date of birth and any other date, in years, months and days, and in total months, weeks, days, hours, minutes and seconds.
Enter a date of birth and the date you want to measure to, which defaults to today. The calculator counts complete years first, then complete months, then the remaining days, the same way people usually state their age. It also converts the total span into months, weeks, days, hours, minutes and seconds, and shows the weekday you were born on and how long until your next birthday.
Every unit is computed from the actual calendar, so leap years and months of different lengths are handled exactly. Times of day are not used: each date counts from midnight, so the hour, minute and second totals are whole days multiplied out.
Counting age in years, months and days has a subtle point: months have different lengths. When the day of the month in the second date is smaller than the day of birth, the calculator borrows the number of days in the previous month. Someone born on January 31 is one month old on the last day of February in most counting conventions, which is why two tools can occasionally disagree by a day near the end of a month.
People born on February 29 celebrate a true birthday only every four years. Legally, many jurisdictions treat March 1 as the birthday in common years when deciding matters such as the age of majority, while others use February 28. This calculator uses March 1 for the next-birthday countdown.
The common international convention, used here, counts age from zero at birth and adds a year on each birthday. Not every culture has counted this way. In traditional East Asian age reckoning, a baby is one year old at birth and everyone gains a year at the Lunar New Year, so a person could be two years older by that count than by the international one. South Korea formally standardized on the international method for legal and administrative use in 2023, and Japan and China use it in law as well, though traditional counting still appears in some cultural settings.
An exact age matters more often than you might think: eligibility for school enrollment, driving, voting, retirement benefits and insurance pricing all depend on it, as do medical guidelines and growth charts for children.
Frequently asked questions
How is age calculated?
Count the complete years since the date of birth, then the complete months since the last birthday, then the remaining days. The calculator does this from the actual calendar, including leap years.
How many days old am I?
Enter your date of birth and today's date; the calculator shows your age as a total number of days, weeks, hours, minutes and seconds.
When is a February 29 birthday celebrated in other years?
Practices vary. Many people and some legal systems use March 1 in common years, while others use February 28. This calculator counts down to March 1.
Can I find my age on a past or future date?
Yes. Change the second date to any date on or after the date of birth to see the age on that day.
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