Understanding Age Calculation
How Age is Calculated
Age is determined by counting the number of full years, months, and days between the birth date and current date, accounting for varying month lengths and leap years.
Manual Calculation Method
- Calculate years difference (current year - birth year)
- If current month is before birth month, subtract 1 year
- If same month but current day is before birth day, subtract 1 year
- For months: (current month - birth month) + 12 if negative
- For days: current day - birth day, add days in previous month if negative
Example Calculation
Birth Date: March 15, 1990
Current Date: May 10, 2023
Years: 2023 - 1990 = 33
Months: May (5) - March (3) = 2
Days: 10 - 15 = -5 → Use April (30 days) → 30 - 15 + 10 = 25
Final Age: 32 years, 1 month, 25 days
Special Cases
- Leap Years: February 29 birthdays
- Month Ends: Different days in months
- Time Zones: Birth time vs current time
Age in Different Cultures
- East Asian: Born at age 1, add year at Lunar New Year
- Official Documents: Often use completed years only