How this calculator works
This calculator computes exact age in years, months, and days from a birth date to an as-of date. Enter the birth date and as-of date to see the exact age and total days. Use it for age verification, birthday tracking, and date difference calculations. The key inputs are the birth date and the as-of date. The output is the age in years, months, and days, plus the total number of days. Real-world applications include age verification, birthday planning, legal date calculations, and anniversary tracking. The calculator compares calendar dates, adjusts incomplete months, and counts full days between the anniversary date and as-of date. If the as-of date is blank, the calculator uses today. Calendar age is easier to understand when broken into full years, full months, and remaining days. JavaScript date math handles leap years when calculating day differences.