Calculators
Age Calculator
Calculate age in years, months and days from a date of birth.
Results appear here.
What the result means
Age is a calendar count of years, then months, then days. It is not the number of days divided by 365, and a leap year does not add a fake day to every year. The time of birth is ignored because the field is a date. A future date is rejected. If the birth day does not exist in the month being counted, it is clamped to the last valid day of that month, which is the day before the next month starts. In a non-leap year, 31 January plus one month lands on 28 February, not on 1 March, and 29 February lands on 28 February. Later months still use the original day when that day exists, so 31 January reaches 31 March. The count uses whole dates, so a daylight-saving change cannot shorten a day.
Related tools
Questions
Is a leap day handled?
Yes. If the birth day does not exist in the month being counted, it is clamped to the last day of that month. In a non-leap year, 29 February is treated as 28 February, the day before March. A later month still uses day 29 or 31 when that month has it.
Does this include the time?
No. The input is a date, so the time of birth is ignored. Someone born late in the day has the same age here as someone born at midnight. The count changes only when the calendar date changes.
Why not divide the days by 365?
That method drifts across leap days and ignores month lengths. This page counts full years, then full months, then the leftover days. Two people born a year apart on the same date still get one year.