Free birth chart calculator

A birth chart, also called a natal chart, is a map of the sky at the exact moment and place you were born: the Sun, the Moon and the eight planets, each set in one of the twelve zodiac signs and one of the twelve houses. Nothing about it is invented. It is astronomy first, read as astrology second.

The wheel above shows that map the way astrologers have drawn it for centuries: the zodiac around the rim, the horizon running left to right with your rising sign at the left edge, and every planet placed at the exact degree it occupied over your birthplace.

The planets move slowly, but the sky itself turns once every day. Your rising sign, the sign climbing the eastern horizon as you were born, changes roughly every two hours, and the whole house wheel turns with it. Two babies born in the same city on the same day, twelve hours apart, share most planets yet live them through entirely different houses.

That is why this calculator asks for the minute and the city, and converts your local birth time to universal time using the timezone rules that actually applied on that date, daylight saving included. If the time is unknown, it computes a noon chart and says so honestly: the planets hold, the houses stay provisional.

Houses divide the sky into twelve rooms of life: self, money, communication, home, and onward. Placidus, the modern default, divides them by time and produces houses of uneven size. Whole sign, the oldest method, gives each sign one full house. This calculator draws both, one toggle apart.

Neither is wrong. Placidus sharpens charts at middle latitudes, while whole sign stays robust everywhere and is enjoying a revival among traditional astrologers. When a planet changes houses between the two systems, read it as living in both rooms.

Every position is computed, not looked up: a full planetary theory for the planets, a high-precision lunar theory for the Moon, and the classical formulas for the Ascendant, the Midheaven and the Placidus cusps, checked against professional ephemerides to within a fraction of an arcminute.

The computation happens entirely in your browser, from a world-city dataset and timezone history that ship with the page. Your birth details are never sent anywhere: the sky is calculated right where you stand.