無料オンライン年齢計算機
生年月日から数秒で正確な年齢を計算します。年、月、日、週などで結果を表示。
Enter your details
- Enter your date of birth and press Calculate.
無料オンライン年齢計算機で即座に年齢を計算。正確な年齢と次の誕生日までの時間を確認。
How to use the Age Calculator
Pick your date of birth in the first field. By default the tool measures your age as of today, but you can choose any other date in the second field to find out how old you were — or will be — on that day. The result updates with your exact age in years, months and days, and also breaks the same span down into total months, weeks, days, hours, minutes and seconds.
How is age calculated?
Age is measured as the completed time elapsed between two dates. Because months have different lengths and leap years add an extra day, this calculator counts whole calendar years first, then the remaining whole months, then the leftover days — the same method used on official documents. That is why the day-by-day total can differ slightly from a simple "365 days per year" estimate.
Common uses
- Finding your exact age for forms, applications and eligibility checks.
- Counting down the days until your next birthday or a special anniversary.
- Working out the age difference between two people.
- Calculating how old a historical event, building or object is.
Privacy
The calculation runs entirely inside your browser. Your date of birth is never uploaded or stored on any server, so the tool is completely private and safe to use.