How to Calculate and Interpret Your Astrological Birth Chart

Welcome to astrology 101!

When it comes to astrology, horoscopes are only the tip of the iceberg, my friends. Astrology is much more complex — and can be so much more personal. If you’ve been ready for a less generalized approach to the stars and want to go deeper, it’s time to learn about your astrological birth chart. Also referred to as the “natal chart,” this map of the stars uses the exact date, time, and location of your birth to re-create a snapshot of the sky at your precise moment of arrival.

And it’s hyperspecific to you.

Within the folds of this circular map, you’ll find all the planets and celestial objects tracked in astrology, along with the zodiac signs they were occupying — and these locations in the sky at the exact moment of your birth can provide you with personalized insight into your career, love life, friendships, and so much more. Feeling overwhelmed? Fear not! Take my hand; let me walk you through the fundamentals of the birth chart.

First, where do I even find my birth chart?

Back in the day, the only way to calculate a birth chart was by hand, using a protractor and a table known as an ephemeris. Thankfully, we have astrology software now, making it possible to calculate a complete birth chart in less than a second. To that end, TimePassages is my favorite app (available on both iOS and Android) for rendering birth charts, along with the website astro.com.

To pull up a birth chart, whether it be yours or someone else’s, you’ll need the date, time, and location of birth. But keep in mind that the birth chart is an extremely sensitive diagram that requires accurate and precise data. In fact, the birth chart changes every four minutes (more on that later), which is why it’s critical to have an exact time of birth — approximates or estimates can (and will) skew the results. So when in doubt, it’s best to verify the information with a birth certificate, baby book, or parent before calculating.

Seeing your birth chart for the first time can be intimidating. Because it’s filled with unfamiliar symbols, strange numbers, and a whole complicated assortment of shapes and lines, making sense of a birth chart can feel like deciphering ancient hieroglyphics. And, in a way, it sort of is: Astrology is a complex visual language that’s been around for thousands of years. Accordingly, it requires practice (and patience) to understand this intricate symbolic diagram.

Wait, what if I can’t get my exact birth-time data?

While it may seem like a bit much to reach out to the hospital records department, it’s usually a pretty straightforward process. (That’s what archives are for!) Otherwise, sometimes fabled birth-story details can be helpful in narrowing down a window of birth (for example, if a parent remembers “you were born early in the morning” or “I was hungry for dinner”).

If you simply can’t access your time of arrival, you’re not totally out of luck. You can set your time of birth to sunrise on the day you were born. While you won’t be able to determine your ascendant or any of the houses within your birth chart since that’s structured around your exact moment of birth, you will be able to see what signs the other planets are occupying and how those planets relate to one another through aspects (more on that later).

Keep in mind, however, that if you were born on the day a planet changes zodiac signs (for example, the day the moon transitions from Libra into Scorpio), there will be ambiguity surrounding those celestial bodies. In these cases, you may want to work with a professional astrologer on a chart rectification — a bespoke process in which astrologers reverse engineer your birth chart based on notable life experiences.

Okay, now what are all these symbols on my birth chart, and what do they mean?

Every planet and celestial body measured in astrology has a symbol (also referred to as a “glyph”), along with each of the 12 zodiac signs. Taking that a step further, every planet sits within a zodiac sign, so — in a birth chart — different symbols are often stacked next to each other. Phew.

Don’t worry. Let’s break it down.

The Planets

Every planet and celestial object with astrological relevance has a glyph. In your birth chart, the position of these planets (in other words, which house the planets occupy) reveals how (and where) their energy appears in your life. Think of the planets as character archetypes, each tasked with playing a specific role in our lives. Below are keywords associated with each planet, along with how to identify their symbol.

The Signs

If the planets are characters, the zodiac signs are personalities. For instance, if Venus (the planet of love, money, and values) is the character that is all about romance, Venus in the airy zodiac sign of Gemini will express itself through curiosity, communication, and play. Alternatively, if Venus is in mysterious Scorpio, it will express its romantic sensibilities in Scorpionic ways — through intensity, power, and depth. Locate keywords for each sign below, along with their symbols.

Other Points to Know

What are the sections of a birth chart?

You may notice that the chart is divided into different sections — 12, to be exact. These pie slices are referred to as “houses.” Avoid the common misstep of conflating houses with zodiac signs (yes, there are 12, but it’s not the same thing). The houses are a visual expression of Earth’s 24-hour rotation around its axis, which means that each house spans approximately two hours of time.

Each astrological house represents a different area of your life. We start counting the houses at the ascendant, which is located at the nine o’clock position in your birth chart. From there, we move counterclockwise around the wheel, and the houses gradually transition from personal and tangible to interpersonal and abstract. Below are a few keywords for each house to help you familiarize yourself with the regions of the birth chart.

Note that some houses in your birth chart will have “things” inside of them (in just a moment, we’ll identify those “things” as planets), and other houses will not. If you don’t have a planet in a house, it does not mean that the keywords of that house won’t appear in your life. In fact, every house plays a vital role in our birth chart regardless of whether a planet occupies that domain. So if your fifth house of creativity or seventh house of partnership is “empty,” it doesn’t mean that you’re artistically stifled or destined to be alone forever. Don’t panic!

How do I put it all together?

When reading a birth chart, start at a point known as the ascendant (also known as the rising sign). Quite literally, the ascendant refers to the zodiac sign ascending over the eastern horizon at your exact moment of birth. Although the visual location of the ascendant will vary based on astrology software, it’s usually located on or around the nine o’clock position and may be symbolized by a circle with a horizontal line in the middle.

The ascendant represents your perception of reality, along with the recurring patterns, themes, and cycles you encounter throughout your life. This placement establishes the architecture for your entire birth chart. After you’ve successfully identified your ascendant, you’ll begin to scan the chart counterclockwise, moving down and around the circle.

With a basic understanding of houses, planets, and zodiac signs, you’ll be able to start analyzing the birth chart. Once you get the hang of it, the formula for interpretation is pretty simple:

Planet = character
Sign = personality
House = area of life

Planet + sign + house = interpretation

In other words, what is a planet doing, how is it doing it, and in which area of life is it showing up? For example, Mars in Virgo in the third house will be motivated (Mars) through structure (Virgo) through its interpersonal relationships (third house), while the moon in Sagittarius in the 12th house will process its emotions (the Moon) through discovering (Sagittarius) its psychic abilities (12th house).

From there, you’ll be able to get into more complex topics such as aspects, which explores how the planets relate to each other. Say, for instance, your sun (identity) in Libra (diplomacy) in the fourth house (home and family) is at odds with Saturn (discipline) in Aries (autonomy) in the tenth house (career and legacy) — that would create notable tension within the birth chart. Alternatively, planets can also work together harmoniously: Mercury (communication) in Pisces (intuition) in the ninth house (travel and exploration) would be pleasantly supported by Jupiter (expansion) in Cancer (sensitivities) in the first house of personality identity.

There’s a lot to unpack when it comes to your birth chart. My advice? Take your time! Go slow! Your ability to create strong astrological interpretations will be strengthened the more you practice, so don’t be afraid to experiment with narratives and bold observations! Virtual communities like the Constellation Club, run by yours truly, are great resources as well, since it’s helpful to get feedback on your interpretations (especially when you’re just starting out).

But, perhaps most importantly, remember to go at your own pace. One of the mystical axioms I say often is “You will know what you need to know when you need to know it.” And that, of course, includes all things astrology. You will understand as soon as you are meant to … and not a second too late. Trust the process.