Calculate Age in Years, Months and Days
Understand completed years, month-end birthdays and the difference between age and elapsed days.
Choose the date you mean
An age calculation needs a birth date and an as-of date. Today is useful for a birthday, but an application or historical record may ask for age on another date. Enter that date explicitly. The calculator works with calendar dates, so it does not need a birth time or a time zone.
Read completed years first
A person born May 9, 1994 is 32 years, 5 months and 10 days old on October 19, 2026. The years count completed anniversaries. Dividing total days by 365 gives a different measure because leap years add days and calendar months have unequal lengths.
What happens at the end of a month
This tool moves a month-end anniversary to the final valid day of a shorter month. January 31 to February 28, 2026 therefore counts as one calendar month. A February 29 anniversary uses the same clamping convention. That explains the displayed result; it does not decide legal birthday rules.
Use the right result
Completed years suit an ordinary age description. Total days suit comparisons of elapsed calendar time. For eligibility or an official form, follow the organization’s stated rule. Check that the as-of date is after the birth date, particularly when copying dates from a document with a different day/month format.
Put it into practice
Age Calculator
Calculate age in completed years, months and days on any chosen date, along with the total number of days between the dates.
Date & calendarDate Duration Calculator
Find the number of days, weeks, and calendar years, months and days between two dates. Choose whether to include the end date.
Date & calendar