Age Calculator — Years, Months and Days

An age calculator with exact years, months, days and a birthday countdown

Runs in your browser · nothing is uploaded

Date of birth

Age on date

Enter a date of birth to see the age instantly.

What it is

An age calculator that goes further than a single number. Give it a date of birth and it returns your age in completed years, the exact split into years, months and days, the total days and weeks you have lived, and how long until your next birthday. Because many visitors also have family or paperwork connected to Korea, it adds the year-based age and the traditional Korean counting age for comparison, plus the Chinese zodiac animal.

How to use

Pick your date of birth from the calendar or type it in.
The reference date is today when the page opens. Change it to find an age on any other day, past or future.
Read the results: age, exact years/months/days, days lived, next birthday and zodiac.
Use the copy button next to the age if you need the text.

How it works

Plain dates: only the calendar year, month and day are used. No time zone conversion happens, so a date never shifts by one day.
Age: the count of birthdays reached on the reference date. Months and days come from adding whole months to the birth date; when the target month has no matching day, its last day is used (Jan 31 plus one month is Feb 28 or 29).
Total days and weeks: the exact number of calendar days between the two dates, with weeks and leftover days.
Year-based age: reference year minus birth year, ignoring the birthday.
Korean counting age: reference year minus birth year plus one. Shown for reference only.
Zodiac: derived from the Gregorian year; 2020 is the Rat year. Lunar New Year boundaries are ignored on purpose.
February 29: in non-leap years the birthday falls on February 28.

Examples

With a reference date of March 10, 2024:

Date of birth	Age	Year-based	Korean count
1990-05-15	33 (birthday not yet)	34	35
2000-01-01	24	24	25
2000-02-29	24 (birthday passed)	24	25

FAQ

How is age calculated?

Age is the number of birthdays completed by the reference date. Subtract the birth year from the reference year, then subtract one more if this year's birthday has not happened yet. On the birthday itself you have already turned the new age.

How are February 29 birthdays handled?

In years that are not leap years, this calculator treats February 28 as the birthday. Some people and institutions use March 1 instead, so check the rule that applies if the date matters for a form or contract.

What is Korean age?

Korea traditionally counted a baby as 1 at birth and added a year every January 1. Korea switched its legal age to the international age in June 2023. The calculator shows the traditional count for reference only.

Is the zodiac sign exact?

It is simplified. The animal comes from the Gregorian birth year, while the traditional zodiac changes at Lunar New Year or Lichun, so people born in January or February can belong to the previous animal.