Age Calculator: How to Calculate Age Accurately
Learn different methods to calculate age, handle leap years, and understand age calculation across cultures.
Calculating age seems simple, but handling edge cases like leap years, different calendar systems, and cultural conventions adds complexity.
The Basic Algorithm
Age = current year - birth year. But if the birthday hasn't occurred yet this year, subtract 1. The key is comparing month and day, not just years.
Leap Year Considerations
People born on February 29 technically have a birthday only every 4 years. Most legal systems recognize March 1 as their birthday in non-leap years.
Cultural Variations
East Asian age reckoning counts age from 1 at birth and adds a year at the lunar new year. This can make someone 2 years older than the international standard.
Programmatic Calculation
In JavaScript: calculate the difference in milliseconds between now and the birth date, then convert to years. Account for whether the birthday has passed this year.