Accurate astronomical calculation
Your Sun sign, beyond a date-range lookup.
Cusp dates vary slightly by year and timezone. Calculate the Sun’s actual tropical longitude for your birth moment.
What this calculator uses
The tropical zodiac begins at the March equinox and divides the ecliptic into twelve equal 30-degree signs. Your Sun sign follows directly from its normalized longitude.
Birth time rarely changes the Sun sign, except close to an ingress. Supplying a recorded time resolves that boundary accurately.
All positions use the tropical zodiac. When time is known, houses use the Placidus system. Calculations are deterministic; no AI is used to produce astronomical coordinates.