Moon Sign Calculator

What is a Moon sign?

A Moon sign is the zodiac sign the Moon occupied at your exact time of birth. Where the Sun sign describes the self you present and grow into, the Moon sign describes the self that shows up when you're tired, scared, comforted or in love: your emotional reflexes, your idea of safety, the way you were mothered and the way you mother yourself.

In practice, people often recognise themselves more in their Moon sign than in their Sun sign, especially in private life. If your horoscope has never quite fit, this is usually the missing piece.

How is your Moon sign calculated?

The Moon is the fastest-moving body in the chart. It travels about 13 degrees of the zodiac a day and completes a full circle in 27.3 days, so it spends roughly two and a quarter days in each sign. Your Moon sign is simply which of the twelve 30-degree segments the Moon was in at your birth moment.

This calculator converts your local birth time to universal time using the time zone of your birthplace, computes the Moon's geocentric ecliptic longitude for that instant with an astronomical ephemeris, and maps it to the tropical zodiac, the system used in Western astrology. Everything runs in your browser; nothing you enter is sent anywhere.

Reference: the Moon's sidereal orbital period is 27.32 days (NASA Moon fact sheet), which gives an average of 2.28 days per sign.

What if I don't know my birth time?

Tick "I don't know my birth time" and the calculator checks the whole day. Because the Moon changes sign every 2.28 days, it changes sign at some point during about 44% of calendar days. If the Moon stayed in one sign for all of your birthday, your result is certain. If it moved, the tool tells you the exact local time of the change and gives you both readings, so you can see which one fits.

Worth trying first: birth certificates in many countries record the time, hospitals keep records for years, and a parent often remembers "just before dinner" well enough to place you on one side of a sign change.

Moon sign, Sun sign and rising sign

These three are the "Big 3" of a birth chart. The Sun sign is your core identity, the Moon sign your emotional nature, and the rising sign the surface others meet first. You need only a birth date for the Sun, a date and time for the Moon, and a date, time and place for the rising sign. If you're new to this, start with rising sign vs Sun sign, then come back and place your Moon between them.

The twelve Moon signs at a glance

Water Moons (Cancer, Scorpio, Pisces) feel first and think second; read the water Moon signs guide for the full picture. And if you and someone close have Moons that don't get along, the Moon sign compatibility post explains why Sun signs can match while you still clash.

Frequently asked questions

Is this Moon sign calculator accurate?

Yes. It computes the Moon's actual position for your birth moment using an astronomical ephemeris (the same kind of calculation professional astrology software uses), then maps it to the tropical zodiac. The one thing it cannot fix is a wrong birth time: the Moon moves about half a degree an hour, so an error of a few hours only matters if you were born close to a sign change, and the tool tells you when that is.

Do I need my birth place for a Moon sign?

Only the time zone. Unlike your rising sign, the Moon sign does not depend on where on Earth you were born, but converting your local birth time to universal time does. Picking the city nearest your birthplace gives the tool the right time zone and its historical daylight-saving rules.

Is my Moon sign the same as my horoscope sign?

No. The sign most people call their horoscope sign is the Sun sign, based on birth date alone. The Moon sign is the sign the Moon occupied at your exact birth moment. Since the Moon changes sign every two to three days, people born in the same week can have different Moon signs.

Why do different websites give me a different Moon sign?

Usually one of two reasons. The site may use the sidereal zodiac (common in Vedic astrology), which sits about 24 degrees behind the tropical zodiac used here and in most Western astrology, so a late-degree Moon can shift back a sign. Or the site ignored your time zone and treated your local time as universal time. This calculator uses the tropical zodiac and real time-zone data.

Can twins or people born on the same day have different Moon signs?

Yes, if the Moon changed sign during that day, which happens on roughly 44% of calendar days. Someone born at 9 a.m. can have a Cancer Moon while someone born at 9 p.m. the same day has a Leo Moon. Enter your birth time to see which side of the change you fall on.