Age Calculator

Age is measured in completed years from your birth date to today: you turn a new age on each anniversary of your birth date, not at New Year. The tool also breaks the remainder into months and days using real calendar month lengths, so the result matches how ages are stated on official documents in most countries.

Your age still advances every calendar year — the anniversary simply has no date in non-leap years. Many jurisdictions legally treat March 1 as the anniversary in common years (February 28 in others), so a person born on 2000-02-29 turns 25 on 2025-03-01 in those places. The calculator counts full years across the February gap correctly either way.

The traditional Korean age system counted you as 1 at birth and added a year every January 1, so it runs 1–2 years ahead of international age. Since 2023-06-28, South Korean law standardizes on international (completed-years) age, which is what this calculator reports. People may still informally quote their Korean age.

Technically at the anniversary of the moment you were born — if you were born at 8 PM, you complete a year at 8 PM on your birthday. Everyday practice uses the calendar date and ignores the hour. This calculator compares dates only, which matches how ages are used on forms and identification.

The calculator uses your device local date. If you were born in a time zone far from where you are now and your birth time fell within a few hours of local midnight, the calendar date comparison could differ by one day from a time-zone-aware calculation. For everyday purposes this difference is irrelevant.

This tool always measures to the current date. To find your age at a past or future date — for example on a contract start date or an exam day — use the Date Calculator: enter your birth date and the target date and read the years, months, and days between them.