Date & Time
Age Calculator
Find your exact age in years, months, and days. Includes total days, weeks, hours, and days until your next birthday.
Date of birth
Your age
36 years, 6 months, 26 days
Next birthday in 158 days.
Total days
13,356
Total weeks
1,908
Total months
438
Total hours
320,544
Frequently Asked Questions about the Age Calculator
How is age calculated?
The calculator subtracts your birth date from today using calendar arithmetic: years first, then months, then days, borrowing across month boundaries the same way Python's relativedelta and Java's Period.between do. The result breaks your age into years, months, and days, and also shows totals in days, weeks, months, and hours.
Why is my age different from other calculators?
Different tools apply different rounding rules. Some show only whole years, some count a partial day as a full day, and some skip the month-borrow step. This calculator uses strict calendar arithmetic: born Jan 31, checked Mar 1 in a leap year returns 1 month and 1 day, matching the common Python and Java date standards.
Does this calculator handle leap years?
Yes. JavaScript's Date object accounts for leap years, including the every-400-years exception. If you were born on Feb 29, the calculator treats your birthday as Mar 1 in non-leap years, which is JavaScript's native behavior when Feb 29 does not exist in a given year.
How many days until my next birthday?
The calculator shows that count directly below your age. If today is your birthday, it counts forward to next year's date rather than showing 0. A Feb 29 birthday lands on Mar 1 in non-leap years, consistent with how the rest of the calculation handles that date.
Why are months and days shown alongside years?
Whole years alone miss context that matters: a 6-month-old is not described as "0 years old," and a 364-day gap between siblings differs from 365. The month-and-day breakdown is what you need for milestone tracking, pediatric growth charts, and age rules that count in months.
Can I check my age on a future date?
No. This calculator computes your age as of today, and the birthday field is capped at the current date, so you cannot enter a future date. To see your age on a specific later day, count the days to your next birthday shown here, or use a date-difference calculator for two arbitrary dates.