Sun Moon Rising Sign Calculator

Your Sun, Moon and rising signs are the three placements astrologers call the "big three", and together they are the shorthand version of a birth chart. The Sun sign is the one you already know: it is the zodiac sign the Sun occupied on your birthday, and it is read as your core identity and sense of purpose. The Moon sign is the sign the Moon occupied at the moment you were born, and it describes emotional nature, instinct and what makes you feel safe. The rising sign - properly the ascendant - is the zodiac sign that was climbing over the eastern horizon at your birth time and place, and it stands for first impressions and the way you instinctively approach anything new.

The three need very different amounts of information, which is why so many people know only one of them. The Sun moves about one degree a day, so a date alone settles it except on a cusp. The Moon covers roughly thirteen degrees a day - a whole sign every two and a half days - so on about two days in five it changes sign partway through, and a birth time is what tells the two apart. The ascendant is the demanding one: the Earth turns a full circle in twenty-four hours, so the rising sign changes about every two hours and depends on the latitude and longitude of the birthplace as well as the exact minute. Two people born the same day in the same city can share a Sun and a Moon and still have completely different ascendants.

This calculator computes all three from the astronomical positions rather than from a lookup table of date ranges. It uses the standard algorithms in Jean Meeus's Astronomical Algorithms for the solar and lunar longitudes and for local sidereal time, applies the historical time-zone rules for your birthplace, and reports each placement to the arcminute. Everything runs in your browser: the birth details you type are never uploaded, logged or stored. Where the answer genuinely is not certain - an unknown birth time, a placement sitting on a cusp, a clock that went back the night you were born - it says so instead of guessing.