Age Calculator
Exact age in years, months and days — plus every other unit.
How it works
Exact age counts calendar years, then whole months, then remaining days — which is harder than it sounds, because months have different lengths and February changes size every four years.
The correct method borrows the way subtraction does: if the day of the month has not been reached yet, borrow days from the previous month; if the month has not been reached, borrow twelve months from the year.
Common questions
Why don't total days match years times 365?
Leap years. Roughly one year in four has 366 days, so 30 years contains about 7 extra days beyond 30 x 365.