Frequently asked questions about age

How is the exact age calculated?

The calculator counts the full years since the last birthday, then the full months and the remaining days, the same way people count age in everyday life and in most laws.

What happens to people born on 29 February?

In common years there is no 29 February, so you choose whether the birthday counts on 28 February or on 1 March. Customs and laws differ from country to country.

What is the difference between 만 나이, 연 나이 and 세는 나이?

만 나이 counts full years since birth and has been the legal standard in South Korea since 28 June 2023. 연 나이 is the current year minus the birth year, still used by a few laws. 세는 나이 starts at 1 at birth and adds one year every 1 January.

Why is the Chinese zodiac different for people born in January or February?

The Chinese zodiac year starts at Chinese New Year, which falls between 21 January and 20 February, so people born before that date belong to the previous animal.

How the age calculator works

This age calculator shows your exact age in years, months and days from a date of birth up to today or to any reference date you choose. It also gives the same age as total months, weeks, days and hours, counts down to the next birthday and tells you its day of the week, and shows the weekday you were born. Each result includes your Western zodiac sign, your Chinese zodiac animal and the East Asian age systems used in South Korea, Japan and China. It is useful for forms, official documents, school and sports eligibility, birthdays and family history.

The calculator counts the full years since the last birthday, then the full calendar months and the remaining days, with end-of-month clamping. People born on 29 February can choose whether the birthday falls on 28 February or on 1 March in common years. South Korea has used 만 나이 as the legal standard for civil and administrative ages since 28 June 2023, shown next to 연 나이 and 세는 나이. Japan's 満年齢 follows the Act on Calculation of Ages of 1902, shown next to the traditional 数え年. In China, 周岁 is the exact age and 虚岁 is counted from Chinese New Year, using Hong Kong Observatory calendar data.

Example: someone born on 15 May 1990 is, on 24 October 2026, 36 years, 5 months and 9 days old, which is 13,311 days or 437 months. The next birthday, 15 May 2027, is a Saturday, 203 days away. The Korean ages are 36, 36 and 37, the Japanese 数え年 is 37, the birth year is 平成2年 with the 干支庚午 (horse), and the Chinese 虚岁 is 37. The time and the time zone of birth are not taken into account, so the hour totals are approximate and based on whole calendar days.