Age
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Your exact age in every unit that matters, plus a visual calendar of the start and end dates.
This walks month by month between your two dates for a calendar-accurate breakdown, then re-expresses that same span as total months, weeks, days, hours, minutes, and seconds — since a legal document, a science project, and a birthday card all want a different unit. The calendar view shows exactly which month each date falls in.
age = target date − birth date, normalized to Y / M / D, then re-expressed in every other unit
This calculator walks through actual calendar months, accounting for different month lengths and leap years, which is more accurate than dividing total days by 30.44.
If your birthday falls exactly on the "as of" date, it's already happened this year, so the calculator shows the anniversary one year ahead.
Yes — the calendar view and every unit total (days, hours, etc.) correctly account for leap years.