🎂 Age Calculator
Find your exact age in years, months, and days, plus total days lived and a countdown to your next birthday.
About Age Calculator
This calculator finds your exact age — or the time between any birth date and a reference date — broken into complete years, months, and remaining days, the same way you'd count by hand on a calendar rather than just dividing total days by 365. It also shows total days and weeks lived, and a countdown to the next birthday, which is handy for things like eligibility checks, milestone planning, or just satisfying curiosity about an exact age down to the day.
The calculation counts whole years first, then whole months within the current year, then whatever days are left over — correctly handling that months have different lengths (28–31 days) and that leap years add a day to February. Because of this, someone born on February 29 still gets an accurate age calculation; their birthday in the age-in-years sense lands on their actual birth date once every four years, and the day count between anniversaries reflects that.
The result is a calendar-date calculation, not a precise elapsed-time measurement — it doesn't account for time zones or the exact hour someone was born, since only dates are entered. You can set the "as of" date to anything, not just today, to calculate someone's age at a past or future point, such as on a specific contract or eligibility date.
Frequently asked questions
How is age calculated exactly?
By counting complete years, months, and remaining days between your birth date and the target date — the same way you'd count on a calendar.
Why might this show a different age than another calculator?
Small differences usually come from how partial periods are handled — some tools round to the nearest year instead of counting exact years, months, and days, or use a fixed 365-day year instead of real calendar dates. This calculator counts complete calendar units, which matches how most legal and administrative age requirements are defined.
Does this handle a February 29 birthday correctly?
Yes. Leap year birthdays are counted using actual calendar dates, so the year, month, and day breakdown stays accurate whether or not the target year is a leap year.
How is "total days lived" different from age in years?
Age in years counts only complete years; total days lived is the full number of calendar days between the birth date and the target date, with no rounding — useful for exact day-count milestones like a 10,000-day birthday.
Can I calculate someone's age as of a future or past date instead of today?
Yes — change the "as of" date to any date you want. This is useful for checking age eligibility on a specific date, like a school cutoff, a contract start date, or an event in the past.