Age Calculator

Age calculation determines the time elapsed between the date of birth and the current (or specified) date. The age is typically expressed in years, months, and days.

How Age Is Calculated:

1. Years: The difference between the years of both dates.
2. Months: The difference between the months, adjusted if necessary.
3. Days: The difference between the days, adjusted for the number of days in each month.

Adjustments are necessary when the current day of the month is earlier than the birth day of the month, or when the current month is earlier than the birth month.

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Age calculation is more than just counting years. While most people think of age in terms of years, a precise age calculation also accounts for months and days. This is particularly important for legal documents, eligibility requirements, and developmental milestones.

Different cultures and regions have varying traditions for calculating age. In some East Asian countries, for example, a person is considered one year old at birth and gains another year on New Year's Day rather than on their birthday. This is known as the "East Asian age reckoning system." In contrast, most Western countries use the "anniversary age" system, where age increases on each birthday.

For medical and developmental purposes, infants and young children often have their age measured in more precise units such as months, weeks, or even days. This allows healthcare providers to more accurately track growth and development against established milestones. For premature babies, doctors may use "corrected age" or "adjusted age" calculations based on the expected due date rather than the actual birth date until the child is about 2-3 years old.