birthtime

Birthtime refers to the moment of birth of an individual. It is the precise time of day when a person is born, and it is typically recorded on a birth certificate or medical record along with date and place of birth. Modern records usually note the time to the nearest minute and adjust for the local time zone and daylight saving time in effect at the birth location.

In astrology, birth time is considered essential for constructing a natal chart. The exact time determines the rising sign (ascendant) and the placement of houses, which can influence the interpretation of planetary positions at birth. Because small changes in time can shift chart components, the reliability of astrology depends on an accurate birth time; when time is unknown, practitioners may use partial charts or estimate.

Determining birth time often relies on hospital clocks, obstetric records, or parental recollection. If the exact time is unavailable, it may be marked as unknown or inferred from family records or events around the birth. Time zones, historical shifts in daylight saving rules, and changes in borders can complicate reconstruction for older births.

Legally and administratively, the birth time is typically a clinical detail rather than a requirement for most civil processes, but it can appear on birth certificates and is used in some demographic surveys, genealogical research, and neonatal medical care where precise timing may matter.

Some cultures and historical periods recorded only the date of birth, while others maintained local or solar time systems prior to standardization of time zones. Today, birth time remains a standard data point in many medical, administrative, and astrological contexts.