Leave empty for today. Set a date to know the age on that day (school entry, 1 April, etc.).
Enter a date of birth and the age, traditional count and days lived appear here.
Enter a date of birth to get the exact age in years and months as of today or any date, the traditional Japanese count (kazoedoshi), days lived and days until the next birthday.
FAQ
Can it tell me the school entry year?
Not directly, but set the reference date to 1 April of the year in question and read the full age. A Japanese child enters the school year beginning on the first 1 April after the day following their sixth birthday, so being six on 1 April means starting that April.
What is the zodiac sign based on?
The Gregorian year. Some traditions start the zodiac year at the lunar new year or at setsubun instead, so people born in January or early February are sometimes assigned the previous year's sign. The tool decides mechanically by calendar year, so for births in that window check the previous sign as well.
Does it match how age is counted outside Japan?
Full age is counted the same way in most countries, so it transfers directly. The one difference is that Japanese law turns the age over the day before the birthday, where some countries use the birthday itself. The discrepancy lasts exactly one day, but if a requirement falls on that day, follow the rule of whoever is asking.
What if the reference date is before the birth date?
The person would not have been born yet, so the calculation stops and says so. Negative ages are never displayed.
Is the date of birth stored?
No, and nothing is sent. Everything happens in the page and is gone when the tab closes.