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How Age is Calculated

The age of a person can be counted differently across various cultures. This calculator is based on the most common age system, where a person's age increases on their birthday. For example:

• If someone has lived for 3 years and 11 months, their age is considered 3.
• Their age will increase to 4 on their next birthday, which is one month later.

This system is widely used in most Western countries.

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Age Systems in Different Cultures

In some cultures, age is calculated differently:

1. Including or Excluding the Current Year:

• For example, a person who is 20 years old is considered the same age as someone in their twenty-first year of life.

1. Traditional Chinese Age System:

• In this system, a person is born at age 1.
• Their age increases at the Traditional Chinese New Year, not on their birthday.
• For example:
  • If a baby is born one day before the Traditional Chinese New Year, they will be considered 2 years old just 2 days later, even though they are only 2 days old.

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Handling Edge Cases in Age Calculation

In some situations, calculating age in months and days can be confusing, especially when the starting date is at the end of a month. For example:

• From February 20 to March 20, we count it as one month.
• However, calculating the age from February 28, 2022, to March 31, 2022, can be done in two ways:

1. Method 1: Consider February 28 to March 28 as one month, resulting in one month and 3 days.
2. Method 2: Treat both February 28 and March 31 as the end of the month, resulting in one month.

Both methods are reasonable, but this calculator uses Method 1 for consistency.

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Similar Situations

Similar edge cases exist for other dates, such as:

• April 30 to May 31
• May 30 to June 30

The confusion arises because months have an uneven number of days. In this calculator, we use the first method (counting from the same day in the next month) to ensure clarity and consistency.

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