How to use the result
- Years, months, days — the usual form answer, computed from calendar anniversaries.
- Total months — useful for eligibility rules stated in completed months.
- Total days — the true day count, including leap days.
- Next birthday — days remaining and the age that will be reached.
Why dates are handled carefully
Age is a calendar quantity: the same date in two timezones must produce the same answer. This calculator converts both inputs to UTC midnight and compares calendar fields, so a browser in India and one in UTC−8 agree. Month-end cases such as 31 January are clamped rather than allowed to overflow into March.