Age Calculator
Age Calculator — runs in your browser. Inputs are not stored.
Age calculator
Enter values, then press Calculate.
※ International age is counted from the birthday. Korean age is (reference year − birth year + 1).
How to use
- Enter your date of birth.
- You can change the as-of date. Leave it blank for today.
- Turn Korean counting age on or off.
- Press Calculate to see international (full) age and days until the next birthday.
Key concepts: international age and Korean counting age
International age increases when your birthday has passed. Korean counting age is calendar year minus birth year, plus 1. Laws, government forms, and most online services use international age, so when in doubt, use that.
Example
If your birthday has not occurred yet this year, international age is this year − birth year − 1. Days until the next birthday are shown too, which is handy with anniversaries and D-day counts.
Related: D-day calculator · date calculator · BMI calculator
Frequently asked questions
What if days until the next birthday are 0?
If the as-of date is the birthday, it is shown as today’s birthday.
What about February 29 birthdays?
In a non-leap year, the next birthday is treated as the last day of February that year.
Are inputs sent to a server?
No. Calculation runs only in the browser.
Can I turn off Korean counting age?
Clear the checkbox to show only international age and the next birthday.
How do I use this with D-day or date math?
You can continue with the <a href="/tools/d-day/">D-day calculator</a> and <a href="/tools/date-calculator/">date calculator</a> for anniversaries and day counts.
Last reviewed: 2026-09-04