Black Moon Lilith calculator: what is my Lilith sign?

The Moon's orbit is an ellipse with Earth near one end, so each month the Moon passes a nearest point, the perigee, and a farthest point, the apogee. Black Moon Lilith is the apogee. More precisely, it is the empty focus of the ellipse, the point opposite Earth, seen along the line to the apogee. It is not a body and nothing can be seen there, which is where the name Black Moon comes from.

The line to the apogee turns slowly forward through the zodiac, completing a circle in about 8.85 years. Averaged over time, that gives mean Lilith, which moves evenly by a little over three degrees a month and spends close to nine months in each sign. It never turns retrograde.

Astrology uses several points under the same name, so it helps to know which one you are looking at. This calculator gives mean Lilith, the default in most astrology software and the one most astrologers mean by Lilith. True Lilith, also called osculating Lilith, follows the Moon's actual, disturbed orbit and swings back and forth around the mean point by many degrees within weeks, so the two can fall in different signs.

There is also a Dark Moon Lilith, a supposed second moon of Earth that astronomers never confirmed, and an asteroid named Lilith. Neither is the Black Moon. This calculator shows the Black Moon, so check which of the three a reading means before you compare.

Astrologers read Lilith as the part of you that refuses to be domesticated: desire, anger or independence that you were taught to hide, and that comes back with force when it is pushed down. The name comes from the figure of Jewish folklore who would not submit, and modern readings keep that theme of refusal rather than of evil. Your Lilith sign colors the kind of rebellion; the short readings on this page give the gist for each sign.

Because mean Lilith stays about nine months in a sign, everyone born within the same nine months or so shares it. The personal layer is the house, which changes every couple of hours, and the aspects Lilith makes to your Moon, Venus or Sun. The birth chart calculator shows those planets in full.

With a birth time and place the calculator gives Lilith's house in the Placidus system by default, or in whole sign, Koch or equal houses on the switch. The house shows where the refusal plays out: Lilith in the seventh is often read through relationships, in the tenth through authority and career, in the fourth through family. Lilith within a few degrees of the Ascendant is read as especially visible, because the refusal then shows in the very way you meet the world. Without a time, the house is left open rather than guessed.

Lilith changes sign only about once every nine months, so a changeover on your birthday is rare. When it does happen and no time is given, the calculator shows both signs and the minute of the change in your local time.

Mean Lilith is computed from the mean longitude of the Moon's perigee in the ELP2000-82 lunar theory, as published in Jean Meeus's Astronomical Algorithms, plus 180 degrees. That longitude is measured along the Moon's tilted orbit, so we project it onto the ecliptic, the plane the zodiac is measured in, and add nutation. The Swiss Ephemeris does the same, and in our checks from 1901 to 2099 the two agree to within two arcseconds. The Moon and the planets elsewhere on the site are tested against NASA JPL's Horizons ephemeris; the accuracy page shows the comparison.

Signs are tropical, measured from the spring equinox. The calculation runs in your browser. To show the first line of today's reading, your birth details are sent once to our server, which does not store them.

Your birth date and birthplace are enough for the sign; the birth time adds the house. The calculation runs in your browser and the tool is free. The birth chart calculator shows Lilith with the planets, houses and aspects of your whole chart.

Lilith belongs to the Moon's orbit, so the Moon sign calculator and the North Node calculator are the natural next stops. This calculator gives mean Lilith in the tropical zodiac, and why charts differ explains how the choice of point and zodiac shapes a chart.