Age Calculator
Calculate exact age in years, months, and days as of any date, along with total time lived (months, weeks, days, hours, minutes, seconds), the day of the week you were born, and a countdown to your next birthday.
Enter your date of birth and (optionally) another date to calculate your age as of that date, in years, months, and days, along with total time lived and days until your next birthday.
Understanding Age Calculations
This calculator finds your age using a calendar-based method rather than simply dividing the number of days lived by 365.25. It counts the number of complete years, then complete months, then remaining days between your date of birth and the target date — the same way you'd count age by hand using a calendar, which correctly accounts for varying month lengths and leap years.
Months have different numbers of days (28 to 31), and years have either 365 or 366 days depending on whether they're a leap year, so age can't be computed with simple fixed-length division. A person born on February 29 during a leap year is a special case too — in non-leap years, this calculator treats February 28 as their birthday so an age or 'next birthday' can still be calculated.
Beyond simple curiosity, exact age calculations matter for eligibility checks (voting, driving, retirement, or age-restricted purchases), legal and medical contexts (consent, insurance, dosage guidelines based on age), and tracking milestones like anniversaries or countdowns to a birthday.
Frequently Asked Questions
About this calculator
This calculator finds age using a calendar-based method — counting complete years, then complete months, then remaining days between a date of birth and any target date (defaulting to today) — rather than a simple division by 365.25. Alongside the headline age, it shows total time lived broken into several units, the day of the week the person was born on, and how many days remain until their next birthday.
- Calendar-accurate age — Age is calculated as complete years, months, and days using real calendar math, correctly handling varying month lengths and leap years.
- Age as of any date — Calculate age as of today by default, or choose any other date to find out how old someone was (or will be) on that specific day.
- Total time lived — See your age broken down into total months, weeks, days, hours, minutes, and seconds, not just years.
- Day of the week you were born — Instantly find out which day of the week your date of birth fell on.
- Next birthday countdown — See the exact date of the next birthday and how many days remain until it, including correct handling of people born on February 29.