Calculate exact age in years, months, and days from date of birth.
The Age Calculator finds the precise age in years, months, and days from a date of birth to today (or a custom target date). It accounts for varying month lengths and leap years. Common uses: verifying legal age thresholds (18, 21, 65), calculating age for medical forms, checking eligibility criteria with age cutoffs, and determining age for insurance or pension calculations.
The main source of difference is how the calculator handles months. March 31 to April 30 is 30 days but only 1 month. Some calculators count calendar months; others count 30-day periods. This calculator uses calendar months (counting to the same day number in the next month).
Legal and medical age is typically expressed in completed (whole) years. A person is legally 17 until the exact calendar date of their 18th birthday — even if they are only hours away.
If you were born on February 29, your birthday in non-leap years is typically treated as either February 28 or March 1, depending on jurisdiction. This calculator uses February 28 as the non-leap birthday.