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年齢差計算機

任意の2つの誕生日の間の年数・月数・日数を算出。

はじめに

Age Difference Calculator — The years, months and days between any two birthdays. Enter Person A birth date, Person B birth date to get an instant, accurate result.

計算式

Difference = |date A − date B|, expressed in both fractional years and total days.

ステップごとの説明

  1. Enter the Person A birth date.
  2. Enter the Person B birth date.
  3. Click Calculate to see your result instantly.

実例

Example: With Person A birth date = 1990-01-01, Person B birth date = 1995-06-15, the Age Difference Calculator gives Years: 5.4511, Days: 1991.

よくある質問

Does the order of the two dates matter?
No, the result is always a positive difference regardless of which date you enter first.
Why is the years figure a decimal?
It accounts for partial years using an average year length (365.25 days), rather than rounding to whole years.
What inputs does the Age Difference Calculator need?
You'll need to provide: Person A birth date, Person B birth date. All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Age Difference Calculator?
The Age Difference Calculator applies the formula exactly as calculated — Difference = |date A − date B|, expressed in both fractional years and total days. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Age Difference Calculator free to use?
Yes, the Age Difference Calculator is completely free, requires no signup, and runs instantly in your browser.

年齢差計算機について

The Age Difference Calculator uses a real, verifiable formula — Difference = |date A − date B|, expressed in both fractional years and total days. — so results are accurate every time, not an approximation.