The Age Calculator determines the exact age or interval between two dates. The calculated age is displayed in years, months, weeks, days, hours, minutes, and seconds. It is based on the most common age system, where age increases on a person’s birthday. For example, the age of a person who has lived for 3 years and 11 months is 3, and their age will increase to 4 on their next birthday one month later. Most western countries use this age system.
In some cultures, age is expressed by counting years with or without including the current year. For example, a person who is twenty years old is the same age as another person who is in their twenty-first year of life.
In one of the traditional Chinese age systems, people are born at age 1 and their age increases at the Traditional Chinese New Year rather than their birthday. For example, if one baby is born just one day before the Traditional Chinese New Year, 2 days later, the baby will be 2 years old even though he/she is only 2 days old.
In some situations, the months and day result may be confusing, especially when the starting date is the end of a month. For example, we count Feb. 20 to Mar. 20 to be one month. However, there are two ways to calculate the age from Feb. 28 to Mar. 31:
▶ If we consider Feb. 28 to Mar. 28 to be one month, the result is one month and 3 days.
▶ If we consider both Feb. 28 and Mar. 31 as the end of the month, the result is one month.
Both results are reasonable. Similar situations exist for Apr. 30 to May 31, May 30 to June 30, etc. In our calculations, we use the former method.
Born June 15, 1990. On October 8, 2026, that is 36 full years (the June birthday has passed), plus June 15 → October 8 = 3 months and 23 days. Result: 36 years, 3 months, 23 days.
From January 1, 2000 to December 31, 2025: January 1, 2000 → January 1, 2025 is exactly 25 years, and January 1 → December 31 adds 11 months and 30 days. Result: 25 years, 11 months, 30 days.
Born March 10, 1995, and today is October 8, 2026. The next birthday falls on March 10, 2027 – 5 months and 2 days away.
The calculator subtracts your birth date from the end date. It counts the full years completed since your last birthday, then the remaining months and days.
Yes. The calculation uses actual calendar dates, so leap years (like 2024) are counted correctly in the total number of days.
Yes - enter any start and end date, not just birthdays. It works as a general date-duration calculator.
Months have different lengths. The calculator counts full months between same-numbered days (for example, Feb 20 → Mar 20 = one month), which is the most consistent method.
No. All calculations happen locally in your browser - nothing is uploaded or stored.
Working with dates? Try the 90 Days From Today Calculator for deadlines and future-date planning.
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