Chronological age refers to the actual amount of time a person has lived, measured in years, months, and days since their birth. It is a straightforward way to determine how old someone is and is often used in various contexts, such as legal documents, education, and healthcare. This age is distinct from other concepts like biological age, which considers physical health and aging, or psychological age, which reflects emotional and cognitive development. Chronological age is a key factor in many societal norms, such as eligibility for school enrollment or retirement benefits.