Age Calculator: Exact Age in Years, Months and Days
Find your exact age from your date of birth, or the age on any date: years, months and days, total months, weeks and days, the day you were born and the countdown to your next birthday.
Today by default. Change it to see an age on a past or future date, such as a deadline.
The same rule is used for months: someone born on the 31st completes a month on the 1st of the next month, or on the last day of a shorter month.
How the age is calculated
- Age is counted in completed years from the day of birth, then completed months, then the days since. It goes up on the birthday.
- For a 29 February birthday, Korea's Civil Act (article 160) and Japan's Civil Code (article 143) end the year on the last day of February, so the age goes up on 1 March in common years. Some people celebrate on 28 February instead; choose that above if you count it that way.
- Under Japan's Act on the Calculation of Age, a year of age is completed at midnight at the end of the day before the birthday, so the law treats that day as the day the age is reached. It decides school years, pensions and other legal ages; the age on the birthday itself is the same.
- Korea also has year age and the traditional counting age. Use the Korean Age Calculator for those.
- Everything runs in your browser. The dates you enter are not sent to LeedyBox or saved.
Source: 국가법령정보센터: 민법 제160조 · Last checked:
Source: e-Gov法令検索: 民法 第143条 · Last checked:
Source: e-Gov法令検索: 年齢計算ニ関スル法律 · Last checked:
Source: 衆議院: 年齢の計算に関する質問に対する答弁書（2002年） · Last checked:
Wrong result? If an age is wrong, email us the dates you entered and the result you expected, so we can fix it.
Does a sentence on this page sound unnatural in your language? Let us know that too.
How to use
- Enter the date of birth. The age is calculated for today straight away.
- To find the age on another date, such as an application deadline, change "Age on".
- Read the age in years, months and days, and the same span in months, weeks and days, with the day of the week you were born.
- For a 29 February birthday, choose whether the birthday counts on 1 March or 28 February in common years. Tick the Japan option to see the day the age is reached under Japanese law.
Frequently asked questions
How old am I exactly?
Count the full years since your date of birth, then the full months since your last birthday, then the days since that monthly date. Born on 15 May 1990, on 13 October 2026 you are 36 years, 4 months and 28 days old.
How do I calculate age on a specific date?
Enter that date in "Age on". Schools, exams and benefits often fix a reference date, such as 1 September or 31 December, and the age on that day decides eligibility.
When does someone born on 29 February turn a year older?
In leap years on 29 February. In other years the laws of Korea and Japan end the year on 28 February, so the age goes up on 1 March. Some people and institutions use 28 February instead; the calculator lets you choose.
Why does Japan say I reach my age the day before my birthday?
Japan's Act on the Calculation of Age counts from the day of birth and ends each year at midnight at the end of the day before the birthday. That is why children born on 1 April start school a year earlier than those born on 2 April.
How many days old am I?
The calculator shows the total days, weeks and months since your birth, and the date you turn the next round thousand of days, such as 10,000 days old. The day of birth counts as day 0; if you count it as day 1, each milestone comes one day earlier.
Is the date I enter sent anywhere?
No. The calculation runs in your browser, and the page does not save what you enter.