How age is counted
Age in years is how many birthdays have happened on or before the chosen date. Months and leftover days are counted from the last birthday-month. Leap-day birthdays are treated as February 28 in common years.
Common questions
Why do some sites differ by one day?
Time zones and whether they count today. This page uses local calendar dates only.
Can I use it for a pet or a company?
Yes. Any start date works.