Moon sign calculator: what is my Moon sign?

Your Moon sign is the zodiac sign the Moon was in at the moment you were born. The Moon crosses a whole sign in about two to two-and-a-half days, so your birth date usually tells you the sign. On a little over four days in ten, though, it switches signs during the day, and then you need your birth time.

Moon sign

Hidden card – fill in your birth data to reveal it

Updated 8 November 2026
How we calculate it
Computed on your device

Enter your date of birth (and time and place if you know them). You get your Moon sign, its exact degree and, if relevant, the moment it moved into the next sign on your birthday.

If you were born on a changeover day and don't know the time, we show both possible Moon signs and the clock time when the switch happened, in your birthplace's local time.

How we calculate it

Planet positions come from Astronomy Engine, an open-source astronomy library (MIT license) whose author documents an accuracy of about ±1 arcminute. We use apparent geocentric positions on the true ecliptic of date (IAU 2006 precession and IAU 2000B nutation, with light-time and aberration) – the same definition most astrology software uses.

Your local birth time is converted to Universal Time with the historical rules of the IANA time zone database, including past daylight-saving changes and war-time clocks. City coordinates and time zones come from GeoNames. If a time was skipped or repeated because the clocks changed, we tell you instead of guessing silently. One honest limit: for births before about 1970 the database is not guaranteed to be complete, and a small town may have kept a different local time than the reference city of its zone. We always show the UTC offset we applied, so you can compare it with what you know (for example a time on a birth certificate).

We test the engine against NASA/JPL Horizons (DE441) for reference birth data: planets agree within 1 arcminute and the Moon within 2; the Ascendant and Midheaven, computed from Horizons sidereal time, agree within 3 arcminutes.

Everything runs in your browser. Your birth data is not sent to a server and nothing is stored.

Why the Moon is the fastest-moving point

The Moon travels about 12–15° along the zodiac per day, compared with about 1° for the Sun. It completes the zodiac in about 27.3 days (the sidereal month). That speed is why the Moon sign can change on your birthday and why your birthplace's time zone matters.

Questions

What is my Moon sign by date of birth?

Enter your date of birth in the calculator. If the Moon stayed in one sign all day, the date is enough. If it changed sign that day, we show the time of the change so you can match it with your birth time.

Do I need my birth time to find my Moon sign?

Often not, but sometimes yes. The Moon changes sign roughly every 2–2.5 days, so on changeover days the birth time decides it. The calculator tells you which case applies.

What does the Moon sign mean in astrology?

Traditionally the Moon describes your emotional style – what helps you feel safe, how you react and what you need to recharge – while the Sun describes your core identity.

What is the difference between Moon sign and Sun sign?

The Sun sign depends on the time of year and is shared by everyone born in about a month. The Moon sign changes every couple of days, so it is more individual.

Is the Moon sign the same as the Moon phase?

No. The Moon sign is where the Moon was in the zodiac; the phase is how much of it was lit, which depends on its angle to the Sun. You can see your birthday Moon phase in the Moon phase tool.

Sources

Astrology, numerology and the Chinese zodiac are offered for entertainment and self-reflection. They are not scientifically validated and are not a substitute for professional advice (medical, psychological, legal or financial). Astronomical positions are calculated precisely; interpretations are traditional symbolism, not predictions.