🇰🇷 Korean Age Calculator
Find your traditional Korean counting age (se-nai) alongside your standard international age (man-nai) for comparison.
How Korean age counting works
Traditional Korean age (se-nai) counts a baby as already 1 year old at birth, and everyone gains a year together on New Year’s Day (January 1st) rather than on their individual birthday. This is different from international age (man-nai), which counts from 0 and increases on your actual birthday.
The formula
Korean age = Current year − Birth year + 1. This depends only on the year, not the exact birth month or day, since the whole country ages up together on New Year’s Day.
Since June 2023, South Korea officially adopted international age (man-nai) for most legal, medical, and administrative purposes, though the traditional counting age is still used informally in everyday conversation. This calculator shows both for comparison.