Age Calculator
Exact age in years, months and days, total days and hours, the weekday you were born and a next-birthday countdown — from a solar or Korean lunar birth date.
Exact age
Result
Enter your date of birth to see your exact age.
How to use
- Type or pick your date of birth in the ‘Date of birth’ field.
- Born on a lunar date? Switch the calendar to Lunar, type it as YYYY-MM-DD and tick ‘leap month’ if it was a 윤달 — the solar date is worked out for you.
- Leave ‘Age at the date of’ empty for today, or set it to check your age on another date.
- Born on 29 February? Choose 1 March or 28 February as the anniversary in non-leap years.
- Open ‘Other age systems’ and ‘Milestones’ for Korean age and the dates you turn 18, 30 or 65.
- Copy any result card, or use Share link to send the same birth date to someone else.
FAQ
How is exact age calculated?
Years, then months, then days are subtracted in that order, with the day count taken from the last month boundary before the target date. That gives a calendar-exact age such as "36 years, 3 months, 18 days" rather than an average-based approximation.
What age is someone born on 29 February in a non-leap year?
There is no 29 February that year, so a convention is required. This calculator uses 1 March by default, the usual legal convention in the US and Korea, and you can switch it to 28 February.
Can I use a lunar (음력) date of birth?
Yes. Choose Lunar and enter the Korean lunar date; it is converted with the Korea Astronomy and Space Science Institute tables (1000–2050) and every age figure uses the resulting solar date, which is also what legal age is based on. The next-birthday countdown follows the lunar date, so it lands on a different solar day each year; a leap-month birthday falls on the regular month in years without that leap month.
Why do age calculators disagree about the number of months?
Some divide the total days by an average month of 30.4375 days. This tool counts real calendar months and shows the averaged number separately, clearly labelled, so both figures are visible.
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