Calculate the age or interval between two dates.
The way a person’s age is calculated can vary across cultures. This calculator uses the most common method, where a person’s age increases on their birthday. For example, someone who has lived for 3 years and 11 months is considered 3 years old, and their age becomes 4 on their next birthday. This method is widely used in most Western countries.
In other traditions, age is counted differently. For instance, a person who is 20 years old may be described as being in their 21st year of life. In one traditional Chinese method, a newborn is considered 1 year old at birth, and everyone’s age increases together at the Lunar New Year, rather than on individual birthdays. For example, a baby born one day before the Lunar New Year would be considered 2 years old two days later, despite being only 2 days old.
Calculating age with months and days can sometimes be confusing, especially at month-ends. For instance, Feb 20 to Mar 20 is counted as one month. However, for a period like Feb 28, 2022, to Mar 31, 2022, two results are possible: counting Feb 28 to Mar 28 as one month gives 1 month and 3 days, or treating Feb 28 and Mar 31 as month-ends gives 1 month. This calculator uses the first method (1 month and 3 days). Similar situations arise with date ranges like Apr 30 to May 31 or May 30 to June 30 due to varying days in each month.