Moon Sign Calculator: What Is My Moon Sign?

To calculate your moon sign, you need your birth date, the time of day you were born (if known), and the city where you were born. An astrology calculator uses these three inputs with ephemeris data to pinpoint the exact zodiac position of the Moon at your moment of birth. AstroCodex does this automatically in about thirty seconds.

Usually yes. The Moon changes signs every two and a half days, so on most birthdays it sits clearly in one sign from morning to night. Only if you were born on a day the Moon transitioned between signs does the exact time become essential. AstroCodex will flag this case and offer both possibilities.

Your sun sign describes your core identity and conscious personality — the "you" you present to the world. Your moon sign describes your emotional, private, instinctive self. The sun is who you are becoming; the moon is who you already are underneath.

Many people say this, and there's a reason. Your sun sign describes the self you are consciously building, which can feel aspirational or partial. Your moon sign describes your unedited emotional reality — the way you felt as a child, the way you react when tired, the comfort you instinctively reach for. It often feels more familiar because it describes what is, not what you're working toward.

The Moon changes zodiac signs every 2 to 2.5 days, moving about 13 degrees of the zodiac per day — the fastest motion of any body in your chart. Over a month it completes the full circle of twelve signs. This is why two people born days apart can have very different moon signs, and why the exact day (and sometimes hour) of birth matters so much for lunar astrology.

In Vedic astrology (Jyotish), the moon sign — called the rashi or janma rashi — is the centerpiece of the chart, often weighted above the sun sign. It is calculated in the sidereal zodiac, which is offset about 24 degrees from the Western tropical zodiac, so your Vedic moon sign may differ from your Western one. AstroCodex calculates both, along with your nakshatra (lunar mansion), so you get the tropical and sidereal picture side by side.

Yes, in a subtle but meaningful way. The phase of the Moon at your birth adds a second layer to your sign. Someone born with a Full Moon in Cancer expresses Cancer energy outwardly and relationally, while a New Moon in Cancer native holds the same emotional depth more privately. Phase colors expression; sign colors substance.

Moon sign compatibility is one of the most important factors in long-term emotional intimacy. Two people can have wonderful sun sign chemistry but clash at the moon level — one needs constant closeness, the other needs space to think. Compatible moon signs mean your emotional rhythms sync, your comforts overlap, and your needs are mutually intelligible.