How age is calculated
Age is worked out calendar-correctly: full years first, then remaining months, then days — accounting for leap years and different month lengths. The “as of” date defaults to today but you can set any date.
Questions
Does it handle leap years?
Yes. February 29th birthdays and leap years are counted correctly.
Can I calculate age on a past or future date?
Yes — change the “age at the date” field to any date you like.
Is my data saved?
No. The calculation runs in your browser and nothing is stored or sent.