How to Use the International Age Calculator
In the United States, age has always been counted one way: you're 0 at birth, and you turn a year older on each birthday. That's called "international age," and it's the standard used by most of the world. This calculator uses that same method - enter a birth date, and it instantly calculates the current age, how many days remain until the next birthday, and the age that birthday will bring.
Korea is a notable exception, and the reason this calculator exists. Until 2023, Korea used three different age-counting systems depending on the context: a traditional "counting age" that starts newborns at 1 and adds a year every January 1st, a "calendar age" that starts at 0 and also increments every January 1st, and international age based on actual birthdays. Having three systems in circulation at once caused real confusion in daily life, contracts, and even legal disputes.
On June 28, 2023, Korea's "unified age-counting law" made international age - the same method the US has always used - the single legal standard for virtually all official and everyday purposes nationwide. The law didn't change anyone's actual age; it simply standardized which counting method applies. This calculator gives you that same internationally standard age for any birth date.
Frequently Asked Questions
Effective June 28, 2023, this law made international age (counted from birth, adding a year on each birthday) the single legal standard in Korea, replacing two older traditional methods that had caused widespread confusion.
The US, like most countries, has only ever used international age, so no such law was ever needed. Korea historically used two additional traditional counting methods alongside it, and the 2023 law eliminated that inconsistency by law.