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Free tool · Moon sign

Moon Sign Calculator: sign, degree, house and phase.

The Moon changes sign every two and a half days, so your Moon sign is not something a birthday alone can tell you. Enter your birth details to get the sign, the exact degree, the house, and your natal lunar phase.

Free, no account. Birth details are used only for this calculation and are not stored. Privacy.

In Western astrology the Moon describes needs, moods, habits and the way you respond before you have decided anything. It is the fastest-moving body in the chart, which makes it both the most personal placement after the Sun and the one most often misreported by tables that round to the day.

This calculator computes the Moon's position for your exact birth minute. If you do not know the time, it uses noon and tells you whether the result sits near a sign boundary, where a few hours would change the answer.

How it is computed

The Moon's geocentric longitude is computed from the JPL DE442 ephemeris for your birth instant, then placed in the Tropical zodiac and in the Placidus house for your birth place. The natal lunar phase is the Sun–Moon elongation at that instant, in the eight-phase model.

The Moon moves about 13° a day, so a birth time known only to the hour still gives a correct sign in the great majority of cases. Only births within a degree or so of a sign boundary need the exact minute.

Common questions

Can I get my Moon sign without a birth time?
Usually. With the time unknown the calculator uses noon; since the Moon covers about 13° a day, the sign is correct unless the Moon was within roughly 6° of a boundary that day. The result tells you if that applies to you.
What does the Moon sign mean?
The Moon describes what you need in order to feel settled and how you respond before you have thought. The sign gives that response a style. The house says where in life it shows most.
What is the natal lunar phase?
The angle between Sun and Moon at your birth, from New Moon through Full and back. It places your birth within the lunar cycle and is read as a broad temperament: emerging, culminating, distributing, releasing.
Why does the Moon sign differ from my Sun sign?
They are two different bodies. The Sun stays in a sign for a month; the Moon for about two and a half days. Most people have different Sun and Moon signs, and the combination is more descriptive than either alone.

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Positions are computed from the JPL DE442 ephemeris in the Tropical zodiac with Placidus houses. Readings are educational, drafted from the computed factors and edited by the Shymea team; they are not the work of a named practising astrologer and are not medical, legal or financial advice. See the editorial policy.