Wherever houses are involved the Placidus system is used, and the birth place time zone is applied with the rule in force on that date.
WHAT IS A MOON SIGN?
A Moon sign is the sign the Moon occupied in the tropical zodiac at the moment of birth. It describes emotional needs, the search for safety, instinctive reactions and the way a person settles down again. Because the Moon crosses a sign in about two and a half days, a birth date alone can leave two candidates; the birth time and place decide between them.
The Sun sign points at the centre of identity and the rising sign at the style turned toward the world, while the Moon sign describes the more private, automatic inner life. These three markers do not have to share a sign.
SUN, MOON AND RISING: THE DIFFERENCE
The big three describe different layers of the same person. Each marker is calculated from a different astronomical position and asks for different birth data.
| Marker | Main theme | Data needed |
|---|---|---|
| Sun sign | Core identity, will and life energy | Birth date; time and place on a boundary day |
| Moon sign | Feelings, habits and the need for safety | Birth date, time and place |
| Rising sign | The outward style and the start of the houses | Birth time to the minute, and place |
HOW IS A MOON SIGN CALCULATED?
- The birth date and time are converted, using the time zone of the birth place, into a single moment of sky.
- The Moon's ecliptic longitude for that moment is found with an astronomical calculation engine.
- The 30-degree slice the longitude falls into gives the Moon sign; the result then links to the matching Moon placement guide.
WHY IS THE BIRTH TIME ASKED FOR?
The Moon changes sign about every 2.5 days. On most days the hour makes no difference, but on a crossing day a few hours can produce two different Moon signs. The calculation engine does not currently return a time-less uncertainty range, so this tool does not guess and asks for the birth time.
Guide to finding your birth time →FREQUENTLY ASKED
What does a Moon sign show?
A Moon sign describes emotional needs, instinctive reactions, habits and the way a person feels safe.
Do I need my exact birth time?
On most days the Moon stays in the same sign all day, so the exact minute does not matter. On the days it changes sign the birth time decides the answer, which is why the tool asks for the time and place rather than guessing.
What house system do you use?
Placidus, wherever houses are involved. A Moon sign itself does not depend on the house system: it comes from the Moon's position in the zodiac, not from the house boundaries.
Can my Moon sign be the same as my Sun sign?
Yes, it can be the same, and it is equally normal for them to differ. The Sun and the Moon move independently, so at the moment of birth they may stand in different signs.
How often does the Moon change sign?
The Moon stays in a sign for about two and a half days and completes its round of the zodiac in roughly 27.3 days.
Where can I read my result?
The link in the result opens the encyclopedia page for the Moon in that sign, which explains the emotional theme of the placement in detail.
How this calculation is made
The result comes from the Moon's actual position at the birth moment, computed astronomically rather than looked up in a rounded table.
The full result is shown for free, and your birth details never enter the address bar — a personal result lives only in the state of the page.