The age of a person can be counted differently in different cultures. This calculator is based on the most common age system. In this system, 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 up 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 even though he/she is only 2 days old. In some situations, the months and day result of this age calculator 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, 2022 to Mar. 31, 2022. If we consider Feb. 28 to Mar. 28 to be one month, then the result is one month and 3 days. If we consider both Feb. 28 and Mar. 31 as the end of the month, then the result is one month. Both calculation results are reasonable. Similar situations exist for dates like Apr. 30 to May 31, May 30 to June 30, etc. The confusion comes from the uneven number of days in different months. In our calculations, we use the former method.

The concept of age can vary across different cultures and systems. This calculator is designed based on the most widely used age system, where a person’s age increases on their birthday. For instance, someone who has lived for 3 years and 11 months is considered 3 years old, and their age will increment to 4 on their next birthday, which is one month away. This system is commonly used in most Western countries.

In other cultures, age may be calculated differently. For example, some systems count the current year as part of a person’s age, while others do not. In traditional Chinese culture, for instance, a person is considered 1 year old at birth, and their age increases at the Traditional Chinese New Year rather than on their birthday. This means that a baby born just one day before the New Year would be considered 2 years old just two days later, even though they are only 2 days old.

There are also nuances in calculating age when dealing with months and days, particularly when the starting date falls at the end of a month. For example, the period from February 20 to March 20 is typically counted as one month. However, calculating the age from February 28, 2022, to March 31, 2022, can be interpreted in two ways:

1. If February 28 to March 28 is considered one month, the result is one month and 3 days.
2. If both February 28 and March 31 are treated as the end of their respective months, the result is simply one month.

Both methods are valid, but this calculator uses the first approach, where the month is counted from the same date in the subsequent month. Similar ambiguities can arise with other date ranges, such as April 30 to May 31 or May 30 to June 30, due to the varying number of days in each month. This calculator addresses these discrepancies by consistently applying the former method for clarity and consistency.