About this Tool

Last updated: 2026-06-13

What is this tool?

This free tool calculates all three Korean age systems from a single birthdate: Korean age (세는나이), international age (만나이), and year age (연나이). It also shows your Chinese zodiac (띠), estimated Korean school grade, and days until your next birthday. The tool is designed for both Koreans and foreigners who want to understand Korea's age systems.

Calculation Method

• Korean age (세는나이): reference year − birth year + 1
• International age (만나이): reference year − birth year, minus 1 if birthday has not yet passed
• Year age (연나이): reference year − birth year
• Zodiac (띠): (birth year − 1900) % 12, cycling through 12 animals from Rat

All calculations are performed entirely in your browser. No data is sent to any server.

Privacy

Your birthdate is never sent to any server. It is stored only in browser localStorage, and share link tokens are encoded entirely in the browser. No account registration or tracking cookies are used. Only site analytics (GA4) and advertising are collected.

Operator

• Operator: bal.pe.kr (personal micro SaaS portfolio)
• Contact: comsamo84@gmail.com
• More tools: bal.pe.kr/tools/

Disclaimer

This tool is for general reference only. For legal disputes, contracts, medical records, or other official age determinations, consult the relevant authority. The results of this tool may differ from official decisions.