Age in Years, Months, and Days
Chronological age from one calendar date to another counts full years, then months, then days — not simple subtraction of year numbers (that ignores birthdays and leap years).
Leap years add February 29 — important when crossing that date.
Next Birthday Countdown
Days until next birthday = difference from today to the next occurrence of the birth month/day. If birthday passed this year, target next year.
Useful for planning — not for legal age determination (see below).
Legal Age vs Calendar Age
Legal age at which you can vote, drink, or contract depends on jurisdiction — some places use completed years, calendar day, or time of birth.
This calculator is for general math — not legal proof of age.
How to Use This Age Calculator
Enter birth date and optionally a reference date (defaults to today). See exact age and days until next birthday — useful for forms, fun facts, and milestone planning.