Moon Sign Compatibility

Moon sign compatibility compares the sign the Moon was in when each of you was born; the tradition reads it as emotional fit, and a Moon-Moon or Sun-Moon aspect between two charts is its strongest sign of that fit.

From two birth dates, the birth chart compatibility calculator places both Moons and shows each person's Moon sign and degree.

What is moon sign compatibility?

Moon sign compatibility is the comparison of the zodiac sign the Moon occupied in each person's birth chart, read for how two people connect on an emotional level. The tradition reads the Moon as emotions, moods, instincts and habits, and the way a person reacts to the people around them, where the Sun stands for the conscious self. Zodiac moon sign compatibility is the same idea under a longer name. It is one layer of synastry, the wider comparison of two charts.

It is a tradition, not a measurement of two people. The best-known controlled test of astrology, published in Nature in 1985, found that astrologers could not match birth charts to personality profiles better than chance.

What does each Moon sign need emotionally?

In the tradition, a Moon sign colours what a person needs to feel settled. The table reads each Moon sign through two things only, its element and its modality, so every row follows a rule you can check rather than a horoscope. Fire needs to act and share enthusiasm, earth needs stability and practical care, air needs to talk things through, and water needs closeness and to be understood. Cardinal signs start, fixed signs hold steady, and mutable signs need room to change.

Which Moon signs are compatible?

The tradition applies the same element rule to Moons that it applies to sun signs:

• Moons of the same element are the easiest emotional fit: two people who need the same kind of thing.
• Fire with air, earth with water are the complementary pairs, read as easy and friendly.
• Every other pairing is read as needing more understanding between the two.

Asked which Moon signs are most compatible for marriage, the tradition gives the same rule for the long run. It adds that Sun to Moon, one person's Sun on the other's Moon, is its classic marriage contact. The full element rule is set out in Zodiac Elements and Modalities: the Logic Behind Every Verdict.

What do Moon-Moon and Sun-Moon aspects mean?

Between two charts, the tradition reads Sun to Moon as one person's sense of self meeting the other's feelings, and it calls it the classic marriage contact. This site's calculator puts it in its heaviest class, alongside Venus to Mars.

Moon to Moon is emotional habit meeting emotional habit, and the calculator puts it in the next class down, with Venus to Venus. Either contact counts as warm when it is a conjunction, a sextile or a trine, and as friction when it is a square or an opposition, because the Moon is a personal planet.

How do I find my Moon sign?

1. Take your birth date.
2. Add your birth time and city, if you know them.
3. Run the birth chart calculator, which shows your Moon sign and its degree for both of you.

The Moon moves about 13 degrees a day and changes sign every two to three days, so without a birth time a birth near a change can show the neighbouring sign. The calculator sets an untimed chart at noon, widens the Moon's tolerance, and says so on the result. That is also the answer for a moon sign compatibility calculator, a sun and moon sign compatibility calculator or a moon sign test for marriage: they are all this one tool, reading two full charts.

Is moon sign compatibility the same as moon phase compatibility?

No. The Moon sign is where the Moon stood in the zodiac at the moment of birth; the moon phase is how much of the Moon was lit on the day of birth. The two tell different things and are read by different tools. The moon phase compatibility calculator on this site is a game that overlays the phases of two birth dates, labelled Game, and makes no claim about emotional fit.