Age Calculator — How Old Am I?

Enter your birth date to get your exact age in years, months, and days, how many days you've been alive, and a countdown to your next birthday.

How to use

  1. Enter your date of birth.
  2. See your exact international age in years, months, and days, plus how many days you've been alive.
  3. Check the countdown to your next birthday.

Most countries use a single 'age' concept — full years elapsed since birth, which is what this tool calls international age. Korea traditionally also used two other counting styles: a 'Korean age' that adds a year at birth and again at every New Year, and a 'counting age' based on the current year minus birth year. Since June 2023, Korean law and administration officially use international age, though a few statutes still reference counting age.

In depth

Age is counted differently in different systems

International age starts you at 0 at birth and adds a year on each birthday. It is the global standard.

East Asian age reckoning starts you at 1 at birth, and everyone gains a year on 1 January. Someone born on 31 December was traditionally 2 the next day.

Year age is current year minus birth year, independent of birthday.

Korea unified its legal ages to the international reckoning in June 2023, though a few schemes still use year age.

Where year age still applies

Military service in Korea is assessed by year age — those turning 19 in a given year.

Alcohol and tobacco purchase uses year age 19, meaning eligibility starts on 1 January regardless of birthday.

School entry is effectively year-based, tied to turning six by a fixed date.

Calculating any of these with international age gives the wrong answer, which is why this tool shows all three.

Edge cases in age calculation

You age on the birthday itself, from midnight.

29 February birthdays have no date in common years. Jurisdictions differ between 28 February and 1 March; this tool uses 1 March.

On the counting basis: legally the birth date is day zero, so "the day you turn 20" is your twentieth birthday itself, not the day before.

Ages that matter legally

Driving eligibility starts somewhere between 16 and 18 in most countries, varying by licence class.

18 is the age of majority in most jurisdictions, and the voting age in many.

In the United States, alcohol purchase starts at 21.

65 is the common reference point for pension and senior benefits, though actual pension ages are rising in many countries and often depend on birth year.

This tool calculates ages; it does not determine eligibility. Check requirements with the relevant authority.

Until your next birthday

The countdown shows the remaining days and which day of the week it falls on — a weekend makes gatherings easier, a weekday needs planning.

Total days lived is shown too. Round numbers like 10,000 days (about 27.4 years) and 20,000 days (about 54.8 years) make good excuses to mark the occasion.

Two people with the same international age can have different year ages depending on whether their birthday has passed — a difference that occasionally matters on forms.

Calculated on your device

Your date of birth is not transmitted; the calculation runs entirely in the browser.

Date of birth is itself sensitive personal data — it is a standard identity verification field — so that distinction is meaningful here.

FAQ

How is exact age calculated?

It counts full years, then the remaining months and days from your birth date to today (or any reference date).

Does it show Korean age?

Yes — alongside the international age it also shows the Korean 만 / 세는 / 연 age styles.

How is a birthday on February 29 handled in non-leap years?

In non-leap years, the countdown treats the closest date (usually February 28) as the substitute, so leap-year birthdays don't disappear.

Method and sources

What this tool bases its numbers on, and how far those numbers go.

What this tool is
Calendar arithmetic, not a legal determination. Which age reckoning a given rule uses is fixed by that rule's own text — this page shows you all three and does not decide which one applies to you.
Formula
International age = completed years since the birth date, then the remaining months and days. Year age = current year − birth year. Korean counting age = current year − birth year + 1. Days alive = the difference in days between the two calendar dates.
Worked example
Born 1990-03-15, evaluated on 2026-08-26: international age 36 years 5 months 11 days, year age 36, counting age 37, and 13,313 days alive.
Limitations
  • It reads the reference date from your device clock. A device set to the wrong date or a different time zone shifts every figure by a day.
  • Months are not a fixed length, so «5 months 11 days» depends on which month boundaries were crossed. Two people the same number of days old can show different month figures.
  • A 29 February birthday has no exact anniversary in common years. The countdown substitutes the nearest date, and jurisdictions do not all agree on which one that is.
  • Korean counting age and year age are shown for reading documents that still use them. They are not the legal age in Korea and have no standing outside East Asia.
  • It does not apply any rule that turns on age — school entry, pension, insurance or contract eligibility all carry their own cut-off definitions.
Sources
Effective date
Last reviewed

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