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Age Calculator
Enter your birthday below to find out exactly how old you are, down to the exact day!
Defaults to today's date!
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Your Age Results
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Years
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Months
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Days
Fun Time Facts
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Total Months
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Total Weeks
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Total Days
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Days to Next B-Day
The Math Behind Age Calculation
Subtraction with a Twist!
Calculating someone's exact age is just a subtraction problem: Today's Date minus Birth Date. However, it’s not as simple as standard base-10 math because our calendar uses different units.
In normal subtraction, when you borrow from the next column, you borrow a "10". But in calendar math, if you borrow a month, you are borrowing 30 or 31 days. If you borrow a year, you are borrowing 12 months!
The "Borrowing" Steps
- Step 1 (Days): Subtract birth days from current days. If the birth day is larger, borrow 1 month from the current month (add 30/31 days to your current day).
- Step 2 (Months): Subtract birth months from current months. If the birth month is larger, borrow 1 year from the current year (add 12 months to your current month).
- Step 3 (Years): Simply subtract the birth year from the newly adjusted current year.
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