How to Calculate Age — Complete Guide
Learn how age is calculated from a birth date, including years, months, days, leap years and common edge cases.
Read guideHow Age Is Calculated — Behind the Algorithm
Understand the calendar math behind age calculation: subtracting dates, handling leap years and counting total days.
Read guideHow Many Days Have I Lived?
Learn how to count every day you have been alive, why the number surprises most people and how to find milestone days.
Read guideLeap Year Birthday — How Age Is Calculated for Feb 29
How age works when you were born on February 29. Learn the legal and mathematical conventions for leap day birthdays.
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