Date and time tool
Calculate an exact age in calendar years, months, and days—with leap years and different month lengths handled for you.
Select the person’s birth date.
Use today or calculate age on another date.
Age result
Your detailed age will appear here
Choose a birth date and the date on which you want to measure the age.
Age guide
Understand why calendar-aware age calculations are more accurate than simply dividing days by 365.
Calendar rule
A leap year has 366 days instead of 365, with an extra day on February 29. It keeps the calendar aligned with Earth’s orbit around the Sun.
Years divisible by 4 are usually leap years.
Century years must also be divisible by 400.
2000 and 2024 are leap years; 1900 and 2100 are not.
February 29
People born on February 29 still become one year older every year. In non-leap years, birthday observance can be February 28 or March 1 depending on personal preference and local legal rules.
This calculator
Uses February 28 as the anniversary reference in non-leap years while retaining the original February 29 birth date.
Helpful answers
Age is calculated as the completed calendar years, months, and days between a birth date and the selected age-at date. The calculator accounts for the actual length of each month.
Yes. A birth date of February 29 is supported. In a non-leap year, this calculator uses February 28 as the displayed birthday reference.
Calendar years can contain 365 or 366 days. Leap years and the different number of days in each month make a direct years-times-365 estimate inaccurate.
Yes. Choose any age-at date on or after the birth date. This is useful for checking age on an application date, event date, or future birthday.
Chronological age is the exact time elapsed since birth, usually expressed in completed years, months, and days. It is different from biological or developmental age.