Two birth dates (ISO)—approximate calendar difference in years, months, and days.
It builds local YYYY-MM-DD dates, orders them, then reports calendar years, months, and days between them (borrow rules for month/day underflow)—not a single total day count and not “age including leap-day” semantics beyond normal Date math.
No. The math for this calculator runs in your browser; values are not uploaded for the calculation.