한국형 날짜 계산기

Korean Age / Military Discharge / Ovulation Calculator — Formulas & FAQ

The Korean Date Calculator combines three essential date calculations for life in Korea — Korean age (만나이), military discharge date (전역일), and ovulation prediction (배란일) — into one tool. 【Korean Age Unification Act (Effective June 28, 2023)】 As of June 2023, South Korea officially adopted the international "full age" (만나이) system in all administrative and legal documents. Under this system, age increases only on birthdays, matching the global standard. The tool also displays "year age" (연나이, birth year subtracted from the current year) and "counting age" (세는나이, the traditional Korean system where you are 1 at birth and gain a year each New Year). Elementary school enrollment year is calculated as birth year + 7. 【Military Service Periods (2024 Standard)】 Army & Marines: 18 months, Navy: 20 months, Air Force: 21 months, Social Service Workers: 21 months. The discharge date and a visual progress gauge are instantly displayed after entering the enlistment date and branch. 【Ovulation Calculation Formula】 Ovulation day = Last menstrual period (LMP) + (cycle length − 14). The fertile window spans from 5 days before ovulation to 1 day after. All dates are displayed on a color-coded mini calendar.

Common Use Cases

How to Use

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   Select a calculation type (Age / Military / Ovulation) from the tabs
2. 2
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   Enter your date or cycle information
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   Results appear instantly — no submit button needed
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   Inputs are automatically saved to your browser for next time

Frequently Asked Questions