The Astrolium Lilith calculator returns Black Moon Lilith by sign and house, with both Mean Lilith and True Lilith on the same output and optional asteroid 1181 Lilith. Math runs on the Swiss Ephemeris in your browser. No login, no email, no upload.
The calculator handles the three different points that share the Lilith name. Black Moon Lilith is the default and runs in two flavours: Mean (h13) and True (h21). Asteroid 1181 Lilith is returned as a separate body code when you request it. For the nodal axis, see the north node calculator and the south node calculator. For the fated-encounter point sometimes layered with Lilith in synastry, see the vertex calculator.
What the calculator returns
Each result lists longitude to the arc-second, the sign and degree, the natal house under your chosen house system, daily motion in degrees, and direction (direct, retrograde, or stationary for True Lilith). Mean Lilith always reads direct at a steady rate. True Lilith can stall, reverse, and accelerate.
The two values can sit in different signs. The calculator shows the gap in degrees between Mean and True positions so you can decide which to read, or read both.
Mean Lilith versus True Lilith versus asteroid 1181
Three distinct calculations. The output names which is which.
Mean Lilith (Swiss Ephemeris body code h13) uses the analytical lunar theory ELP-2000 to compute the second focus of the smoothed orbit. The result is monotonic direct motion at about 40 arc-minutes per day. Mean Lilith is the default in astro.com, Solar Fire, and most modern Western tools.
True Lilith (Swiss Ephemeris body code h21), also called osculating Lilith, solves the instantaneous orbital elements at the moment of the chart. The Moon's orbit is perturbed by the Sun and the major planets, so the true focus oscillates. It can sit 30 degrees from the Mean position and can briefly retrograde.
Asteroid 1181 Lilith is a real body in the main belt, discovered by Benjamin Jekhowsky in 1927. It is the only Lilith with physical existence. Period is roughly 4.4 years. The calculator returns this position when the asteroid option is selected, with its own degree and house separate from the Black Moon values.
How the calculation works
Math runs on the Swiss Ephemeris DE431 kernel, the same library Solar Fire and Astro Gold call. Mean Lilith comes from ELP-2000. True Lilith comes from numerical integration of the instantaneous lunar orbital elements. Asteroid 1181 comes from the asteroid file (seas_18.se1). All three positions match astro.com to the arc-second.
The calculator supports four house systems: Placidus, Whole Sign, Koch, Equal. Switch from the dropdown without re-entering birth data. Whole Sign is the default for traditional readings. Placidus is the default for modern Western.
Nothing is stored. Nothing is emailed. The chart wheel renders client-side from the returned data.
When the asteroid output matters
Most modern readings use Black Moon Lilith and do not pull the asteroid. Two cases where asteroid 1181 is worth running.
A composite chart that shows a tight conjunction between one partner's asteroid Lilith and the other partner's personal planet is a different signal from a Black Moon contact, because the asteroid moves faster and contacts are more precise. The asteroid takes 4.4 years per orbit versus 8.85 for the lunar focus.
A return-chart workup that already has Black Moon Lilith flagged sometimes adds the asteroid for the second reading layer. The two will rarely agree on house or sign, and the disagreement itself is the signal.
After the calculator
The Lilith position reads inside the full chart context. The ruler of Lilith's sign matters. So does any natal aspect from an outer planet. So does whatever transit is currently active.
For the full chart wheel where Lilith sits alongside every other body, see the natal chart feature and the how to read a natal chart guide. For the nodal axis often layered against Lilith, see the south node calculator. For the fated-encounter point, see the vertex calculator. To run Lilith inside a relationship reading, use the synastry calculator on both charts.