Moon sign calculator
Where the Moon was in the zodiac when you were born, and what phase it was in. A date gets you most of the way; a birth time settles it when the Moon changed sign that day.
No time? We use noon and tell you if the Moon changed sign during your birthday.
Why the Moon looked the way it did that night
The phase is just geometry: the Sun always lights half the Moon, and how much of that lit half faces us depends on the angle between Sun and Moon as seen from Earth. Drag to see how the angle changes the phase.
Left: top-down view with sunlight coming from the left. Right: the Moon as seen from the Northern Hemisphere (flip it left to right for the Southern).
The Moon completes the cycle in 29.5 days and crosses the whole zodiac in 27.3, which is why your moon sign and phase don't repeat together on a neat schedule. Want to go deeper into why the Moon changes shape? ahaboo has a narrated explainer on Moon phases you can pause and replay as you go, the same Sun–Earth–Moon geometry as the diagram above, told as a story.
How we calculate your moon sign
We compute the Moon's ecliptic longitude using the main periodic terms from Jean Meeus's Astronomical Algorithms, which is accurate to a few hundredths of a degree for these dates. The Moon moves about 13° a day, a whole sign every 2 to 2.5 days, so on roughly two birthdays in five it changes sign at some point during the day. Birth time matters much more for the Moon than for the Sun.
Your time zone is converted using your browser's time-zone database, which includes historical daylight-saving rules for most places since 1970 and many earlier dates.
More from your birth date
Questions people ask
How do I find my moon sign?
You need your birth date and ideally your birth time and place. The calculator finds the Moon's zodiac position at that moment. Without a time it uses noon and warns you if the Moon changed sign that day.
Can I find my moon sign without a birth time?
Usually, yes. The Moon spends about 2.5 days in each sign, so on most dates it stays in one sign all day. If it changed sign on your birthday, you'll see both options and roughly when the switch happened.
What does my moon sign mean?
In astrology, the sun sign describes your outward identity and the moon sign your emotional needs, instincts and what makes you feel safe. It is a tradition for self-reflection rather than a scientific measure.
What phase was the Moon when I was born?
The result shows the Moon phase and how much of it was lit on your birth date, calculated from the angle between the Sun and Moon.