Understanding Age Calculation Methods

This calculator uses the most common international age system where:

• A person's age increases by 1 on each birthday
• Partial years (months and days) are counted until the next birthday

How Age is Calculated in Different Cultures

Different cultures measure age differently:

1. Western Age System (Most Common)
   • Age increases on a person's birthday
   • Example: A child who is 3 years and 11 months old is considered 3 until their next birthday, when they turn 4.
2. East Asian Age Reckoning (e.g., Traditional Korean & Chinese Systems)
   • A person is born at age 1
   • Age increases at the New Year, not on birthdays
   • Example: A baby born one day before the Lunar New Year becomes 2 years old just two days later, despite being only 2 days old.
3. Other Variations
   • Some cultures count the current year as part of the age (e.g., "21st year of life" = 20 years old in Western counting).

Month & Day Calculation Notes

Age calculations involving months and days can sometimes be confusing due to varying month lengths:

• Example 1:
  • From February 20 to March 20 = 1 month
  • From February 28 to March 31 can be interpreted in two ways:
    • Method 1 (Exact Day Count):
      Feb 28 → Mar 28 = 1 month, then + 3 days → 1 month & 3 days
    • Method 2 (End-of-Month Rule):
      Both Feb 28 & Mar 31 are treated as month-ends → 1 month
• This calculator uses Method 1 (exact day count) for consistency.
• Similar cases:
  • April 30 → May 31
  • May 30 → June 30

How This Calculator Works

• Input: Enter your birth date (day, month, year).
• Output:
  • Exact age in years, months, and days
  • Counts fractional months & days until the next birthday
  • Follows the Western age system (age increases on birthdays)

This ensures the most widely accepted and precise age calculation method.