How to use the age calculator
Enter a date of birth and your exact age appears instantly, along with your age in years, months and days, the number of days you have lived and a countdown to your next birthday. Change the Age on date to see how old someone was (or will be) on any date.
If you only know a birthday on the Korean lunar calendar, switch to Lunar and pick the lunar year, month and day; the calculator converts it with lunar tables from the Korea Astronomy and Space Science Institute (KASI).
Korean age, year age and international age
Traditionally Koreans counted age differently: a baby is 1 at birth and everyone gets a year older on January 1 (Korean age, 세는 나이). Some laws used "year age" (current year minus birth year). Since June 28, 2023, amendments to the Civil Act and Korea’s framework law on public administration make international age the standard for laws, contracts and official documents.
Year age is still used by a few laws, such as the Youth Protection Act (alcohol and tobacco sales are allowed from January 1 of the year a person turns 19) and the Military Service Act. The calculator shows all three side by side.
Chinese zodiac: Lunar New Year or the start of spring?
Your zodiac animal comes from the year in the 60-year cycle. Most people switch animals at Lunar New Year, which falls between late January and mid-February, so people born in January or early February often have the previous year’s animal. Astrology traditions instead start the year at Lichun (start of spring, around February 4). You can switch between the two; the calculator tells you when they disagree.
Leap-day birthdays and zodiac signs
Under Korean civil law, a person born on February 29 is treated as getting a year older on March 1 in common years, and this calculator follows that rule. Western zodiac signs use the usual date ranges (for example Libra Sep 23 – Oct 22); the exact boundary can shift by a day depending on the year.
FAQ
How is exact age calculated?
Subtract the birth year from the current year, then subtract one more if this year’s birthday hasn’t happened yet. You become a year older on your birthday itself.
What is Korean age?
The traditional Korean count: you are 1 at birth and add a year every January 1. It equals year age + 1. Since June 28, 2023, South Korea officially uses international age instead.
Why is my Chinese zodiac animal different from my birth year?
If you were born before Lunar New Year (late January to mid-February), you belong to the previous year’s animal. The calculator checks the exact Lunar New Year date for your birth year.
How many days old am I?
See the Days lived box: it counts the days from your birth date to today, and also shows which day of your life today is and when your 10,000th day falls.
Is my birth date saved?
Only in your own browser so the result is ready next time. It is never uploaded. Press Reset to clear it.