Age Calculator
Find your exact age in years, months, and days — plus total days and next birthday countdown.
How This Age Calculator Works
This free Age Calculator finds the exact time between your date of birth and today (or any target date), then converts that difference into years, months, and days. It also shows total days, weeks, and a next-birthday countdown—useful for forms, eligibility checks, school admissions, job requirements, and travel documents.
Because month lengths vary (28–31 days), calculating age is not the same as dividing total days by 365. This calculator follows calendar-based counting: it first counts full years, then full months, then remaining days.
Age Calculation Formula
Conceptually:
Age = Target Date − Date of Birth Breakdown = Years + Months + Days (calendar-based)
For total days, the tool measures the day difference between the two dates. Leap years are automatically handled by the date system.
Age Calculator – FAQs
How do I calculate my exact age?
Enter your date of birth and click Calculate. Optionally choose a target date to calculate your age on a specific day.
Can I calculate age on a future date?
Yes. Select a target date (for example, your next birthday or an eligibility cutoff date) and the calculator will use that date.
How does it handle leap year birthdays (Feb 29)?
The calculator handles leap years automatically. For Feb 29 births, the next birthday is computed on the nearest valid date in non-leap years.
Is this calculator accurate for legal eligibility?
It's accurate for standard use. For official rules, always follow the definition used by the authority (some count "completed years" only).
Why does age sometimes differ by a day?
Timezone and "inclusive vs exclusive" counting can change results. This tool uses local calendar dates to stay consistent.