⚸ Free Black Moon Lilith Calculator: Mean and True
Umbriel's free Black Moon Lilith calculator finds your Lilith in both the Mean and the True calculation, with sign, exact degree and house.
No account, no email. The two can sit as much as thirty degrees apart, a whole sign, which is why Lilith is the placement websites disagree about most.
- What you'll needBirth date (time and place for the house)
- What you getYour Black Moon Lilith sign, exact degree and house, in both the Mean and the True calculation, side by side
- CostFree, no account required
What Black Moon Lilith is
Black Moon Lilith is not an object. It is the lunar apogee. The far focus of the Moon's orbit, the empty point the Moon is furthest from Earth at. Because it is a point, not a body, there is more than one defensible way to calculate it, and that is the source of nearly every argument about Lilith on the internet.
The Mean Black Moon Lilith is the smoothed, average apogee, moving evenly through the zodiac in about nine years. The True or osculating Lilith is where the apogee is at that instant, and the Moon's orbit is pulled about so hard by the Sun that the true apogee swings back and forth around the mean, sometimes by tens of degrees, and it goes retrograde regularly. Two sites can therefore give you Liliths a full sign apart and both be right about what they calculated.
It gets worse before it gets better: at least two other things are also called Lilith, asteroid 1181 Lilith, a genuine rock, and the hypothetical Dark Moon Lilith, which is a different idea again. If a site does not say which one it means, its answer cannot be compared with anyone else's. Umbriel shows the Mean and the True together and labels them, so you can see the disagreement instead of inheriting it.
How Umbriel computes it
This tool gives the sign and degree of Black Moon Lilith, the Moon's apogee, in two calculations shown side by side. Mean Lilith is a formula in time only: the Moon's mean node and mean argument of perigee are added, 180 degrees are added to turn the perigee into the apogee, and the result moves smoothly around the zodiac and never turns retrograde. True Lilith is the osculating apogee: Umbriel takes the Moon's position from its full lunar series at three instants 0.005 of a day apart, gets the velocity, forms the eccentricity vector of the orbit at that moment, and points opposite it. The two can fall in different signs, because the true apogee swings either side of the mean and does turn retrograde. Neither depends on your birthplace. Both depend on the birth date and, for True Lilith, on the time of day, since it changes within hours. The house Lilith falls in needs a birth time and place. On accuracy, the accuracy page reports True Lilith within 7.2 arcminutes of NASA/JPL Horizons over 1920 to 2044, and all seven Lilith-type points it offers agree with published values on three charts to within 2.2 arcminutes. A sign is 1,800 arcminutes wide, so the sign is only in doubt when Lilith sits within a few arcminutes of a boundary. Lilith here is a calculated point, not a body, and asteroid 1181 Lilith is a separate object that this tool does not compute.
What's in your result
- Mean Black Moon LilithThe smoothed lunar apogee: the version most sites and most books use by default.
- True (osculating) LilithThe actual apogee at your moment, which is what the sky was really doing.
- Both signs and degrees, side by sideSo you can see immediately whether yours is one of the cases where they disagree.
- The house each falls inNeeds your birth time.
- AspectsContacts to Lilith with exact orbs.
- Which one to quoteUmbriel names the calculation on the page rather than leaving you to guess, which is the whole problem with most Lilith readings.
Common questions
Why is my Lilith different on different websites?
Because they are calculating different things. Mean Black Moon Lilith is a smoothed average of the lunar apogee; True or osculating Lilith is the apogee's actual position, which swings around the mean by a large margin and can put it in a different sign entirely. Add asteroid 1181 Lilith and the hypothetical Dark Moon Lilith and there are four candidates. Umbriel gives Mean and True together and says which is which.
What is the difference between True Lilith and Mean Lilith?
Mean Lilith moves evenly, completing a circuit in about nine years. True Lilith is the real osculating apogee, which the Sun's pull drags back and forth. It wanders around the mean position and turns retrograde regularly. Neither is wrong; they are different quantities that share a name.
Which Lilith should I use?
Most books, most courses and most sites default to the Mean, so if you want to be understood in conversation, quote that one. If you want the position the sky was in, use the True. Umbriel gives you both so the choice is yours and visible.
Is Black Moon Lilith a real object?
No. It is a geometric point, the far focus of the Moon's orbit, not a body. Asteroid 1181 is a real rock but is a completely different thing that happens to share the name.
Is this Lilith calculator free?
Yes, both Liliths, with signs, degrees, houses and aspects, and no account or email.
Do I need an account or an email address?
No. There is no sign-up, no email capture and no free trial. Enter your details and the result is drawn in your own browser.
Go deeper
Every one of these is a page in its own right, written out one at a time.
Related free tools
Prints in the head of this page, all public domain except where stated: Triumph of the Moon, Monogrammist P.P. Italian, late 15th-early 16th century, 1500/10, Art Institute of Chicago; The Eclipse, Felix Bracquemond French, 1833–1914, 1869, Art Institute of Chicago; Urania's Mirror, Sidney Hall, 1825, Library of Congress via Wikimedia Commons. Ground: Andreas Cellarius, Harmonia Macrocosmica, 1661, Wikimedia Commons.
Umbriel offers every system here as a set of prompts to think with, never as a statement of fact about who you are. Take what's useful, leave the rest.