How do I calculate my sun, moon, and rising signs?

If you’re just beginning to explore astrology, one of the first steps is learning your sun, moon, and rising signs — often called the “big three.” Together, they offer a more complete picture of your personality than the sun sign alone. But to truly understand what they mean, you need to know how to calculate them accurately.

Each of these signs reflects a different part of who you are, and each one depends on precise birth information.

Your sun sign is based on your date of birth

Your sun sign is the easiest to calculate. It is determined by the position of the sun in the zodiac at the time of your birth and only requires your date of birth.

The sun represents your core identity, your will, your creative energy, and the traits you are growing into over your lifetime. It is the sign most people refer to when they say, “I’m a Leo” or “I’m a Taurus.”

You can find your sun sign using any reliable astrology website or chart calculator, simply by entering your birth date.

Your moon sign is based on the moon’s position at your birth

Your moon sign reflects your emotional world, instincts, and inner responses. It is based on the position of the moon at the time of your birth, which changes sign roughly every 2.5 days. Because the moon moves quickly, even a few hours can make a difference — especially if you were born on a day when the moon changed signs.

To calculate your moon sign accurately, you’ll need:

Your date of birth
Your time of birth (or a close estimate)
Your place of birth

Without the birth time, your moon sign may still be estimated — but it might be uncertain if the moon changed signs on that day.

Your rising sign depends entirely on the exact time and place of birth

Your rising sign (also called the ascendant) is the zodiac sign that was rising on the eastern horizon at the exact moment you were born. It changes approximately every two hours, making it the most time-sensitive part of your chart.

Your rising sign shapes your:

Outer behavior and first impression
Appearance and personal style
Initial reactions to the world
Starting point for the rest of your birth chart (it determines the layout of the houses)

To calculate your rising sign, you need:

Your exact time of birth
Your place of birth

Without this data, your rising sign — and the entire structure of your chart — cannot be calculated accurately.

What if you don’t know your birth time?

If your birth time is unknown, you can still find your sun sign and sometimes your moon sign — as long as the moon didn’t change signs on your birth date. Your rising sign, however, cannot be determined without a reliable time.

In such cases, you might:

Estimate your moon sign based on a noon chart
Use other chart features to explore your personality
Try to recover your birth time from family records or official documents
Ask an astrologer to perform chart rectification (a technique used to estimate birth time)

Discover how your big three work together

Once you have your sun, moon, and rising signs, the real insight comes from understanding how they interact.

Your sun is your core
Your moon is your emotional self
Your rising is the mask you wear to the world

For example, someone with a Cancer sun, Aries moon, and Capricorn rising might be nurturing and sensitive (Cancer), emotionally bold and impulsive (Aries), yet come across as serious and reserved (Capricorn).

Each combination is unique and adds layers to how you relate to yourself and others.

Explore your full chart with a personalized reading

If you’d like to go beyond the basics and discover how your sun, moon, and rising signs fit into the larger story of your personality, a full birth chart reading is the best place to start.

At AstroEnter, you can order a Personal Astrology Birth Chart Reading created from your exact date, time, and place of birth. This in-depth reading explores your big three, your house placements, planetary aspects, and the deeper themes that shape your emotional life, relationships, career path, and personal growth.

Because astrology is more than signs — it’s a complete reflection of you at the moment you entered the world.