How to use it
- Enter the Date you want and a Time if you know it. If you do not know the time, tick I do not know the time: the whole day is then checked.
- Type the Place and pick it from the list, or tick Enter coordinates instead. The place sets the local day.
- Click Calculate. The Moon's sign and degree appear first, then any change of sign that day with its time.
- Read the sign's short meaning under the result, and the change of sign if there is one.
How the Moon's sign is found
The Moon's sign is the twelve-part division of the ecliptic, each part 30 degrees, that contains its geocentric longitude at the moment you choose. The Moon moves about 13 degrees a day, so it passes through one sign in roughly two and a half days. The calculator reads the Moon with astronomy-engine, whose Moon agrees with the NASA JPL Horizons ephemeris to a few arc seconds at the dates checked for this site.
A day is the local day of the place you choose, from midnight to midnight in its time zone, including the days when clocks change. The calculator finds each change of sign during the day and gives the moment to the second.
Time known and time not known
With a time, the result is the Moon's sign at that moment, and any change of sign on the same day is shown with its time. Without a time, the result shows the Moon's sign at the start of the day and every change during it, so you can see the whole day.
- A change close to midnight can fall on the day before or after a birth record shows, depending on the time zone of the place and the time you give.
- The Moon's sign is not the same as the Moon's phase: the phase depends on the Sun, the sign on the Moon's own position.
Worked example: New York, 4 July 1990
At 14:30 daylight time in New York the Moon is at 5°54′ Sagittarius. The Moon started the day in Scorpio and entered Sagittarius at 02:35 that morning, so both signs are shown.
Without a time the same day is shown as a range: the Moon starts the day in Scorpio, changes to Sagittarius at 02:35, and stays there until midnight.
Frequently asked questions
Why does the Moon change sign so often?
The Moon moves faster across the sky than any planet, about 13 degrees a day, so it crosses each 30-degree sign in about two and a half days. A change of sign on a given day is common.
What if the Moon changes sign while I was born?
Then the time of birth decides the sign. Enter the birth time, and the calculator gives the sign at that moment and the time of the change, so you can see how close it was.
Is the Moon sign the same as the Moon phase?
No. The Moon sign is the part of the zodiac, measured from the spring equinox, that the Moon is in. The phase is the Moon's lit shape seen from Earth, which depends on its angle to the Sun. The two are independent.
How accurate is the Moon's position?
The position is accurate to about one arc minute. The time of a change of sign is found by bisection to the second, so it is as exact as the position.
Does this calculator keep the date I enter?
No. The date, time and place stay in your browser and are not stored or sent to us.
Sources
- astronomy-engine, the MIT-licensed library that calculates the Moon's position
- JPL Horizons, the NASA ephemeris used to check the Moon's position
- IANA Time Zone Database, the historical clock rules of each zone
- GeoNames, city coordinates and time zones (CC BY 4.0)
Figures and text last checked on Tuesday, November 10, 2026.