Age calculator
Age counts in complete years from the date of birth: the year is added on the birthday itself, not at the start of a month or a calendar year, and the remainder appears as whole months plus leftover days, the way age is spoken aloud.
- Days lived
- 0
- Until next birthday
- 0 p
How is age calculated exactly?
First come whole years from birthday to birthday, then whole months since the last birthday, and finally the leftover days. When today's day of the month is lower than the birth day, the days are borrowed from the preceding month, so the same gap can yield a different day count in different months.
How does the calculator handle a 29 February birthday?
Someone born on a leap day has no date of their own in a common year, so the arithmetic has to pick one. This calculator completes the year on 1 March, meaning that in a common year the person turns older on the morning of 1 March. Some calendars and apps use 28 February instead.
How many days has a person lived?
Days lived is the count of calendar days from birth until today, leap days included. Thirty years is 30 × 365 = 10,950 days plus the leap days that fell inside them, usually seven or eight. The exact figure depends on which years the span happens to cover.