birthdate

Birthdate, also known as date of birth, is the date on which a person was born. It includes the day, month, and year and is used to determine a person’s age. In most countries birthdates are recorded at birth by civil registration authorities and appear on official documents such as birth certificates and identity cards.

Birthdates serve multiple roles in society. They are essential for calculating age, which governs eligibility for schooling, employment, voting, driving, drinking, and other rights and responsibilities. They are also used in medical records, insurance, travel documentation, and various administrative processes. Because age is a key factor in many decisions, birthdates are treated as sensitive personal data and protected by privacy and data-security rules in many jurisdictions. In genealogical research, birthdates help establish family history, though records can be incomplete or approximate.

Formats and cultural variations can affect how birthdates are written and interpreted. Common formats include year-month-day, month-day-year, and day-month-year, with regional preferences influencing punctuation and zero-padding. Some cultures use lunar calendars or non-Gregorian dating systems, requiring conversion for cross-cultural use. Privacy considerations are important, as incorrect or disclosed birthdates can enable identity theft or misuse. While astrology and other belief systems may assign significance to birthdates, they are not scientifically validated indicators of health or destiny.