About our calculations

Every position on your chart is calculated from your birth date, time and place. The text that explains them is written separately by people, and is never used to work out where a planet is.

The zodiac

We use the tropical zodiac, the system most Western astrology is based on. Signs are tied to the seasons, so the Sun enters Aries at the March equinox. Some traditions, such as Vedic astrology, use a different zodiac and can give a different Sun sign.

Houses

Houses are worked out with the Placidus system. They need your exact birth time, so if you do not know it we do not show your Rising sign or houses, and we tell you when your Moon sign could be one of two signs.

Planet positions

Positions come from the Swiss Ephemeris, a standard astronomical data set. We apply the timezone and daylight saving rules that were in force at your birthplace on your birth date, not today's rules.

Aspects

An aspect is an angle between two points on your chart, such as a trine (120°). We rank them so the most significant appear first, and we leave out pairings of Uranus, Neptune and Pluto, which are the same for everyone born within several years of each other.

Astrology is offered for reflection and entertainment. See our Terms.