How to Compare Astrology Charts

Co-authored by Angel Eyedealism and Glenn Carreau

Last Updated: April 7, 2022 References

It's easy enough to compare your Sun sign to another person's, but how do you compare whole birth charts? Astrology is a lot more complex than it seems, but once you know how to read a chart and what aspects to examine, you can quickly determine compatibility between you and a special someone. We've made a complete guide to comparing astrology charts in a few easy steps to get you started!

Method 1

Method 1 of 3:

Creating Accurate Birth Charts

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Make sure each birth chart has the correct information. You'll need your date of birth (month, day, year), the exact time of birth, and the city and timezone of birth.^{[1]
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Expert Source

Angel Eyedealism
Astrologer & Performance Artist
Expert Interview. 8 December 2021.} You'll also need to get that information from the person whose birth chart you want to compare. Accurate information will ensure a quality compatibility reading when you compare charts later.
- If you have your birth certificate on hand, it'll be easier to get precise information there.
- Gathering information for the other person's chart may be trickier, depending, but you can ask them to check their birth certificate if they're not sure of something.
- If more specific information isn't available, you can still learn a lot from just a date of birth. A person's Sun, Mars, and Venus signs are determined based on birthday alone, and all are vital for reading compatibility!
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Create astrology charts online. Once you have all the information you need, plug it into an online calculator tool to generate complete astrology charts for both of you. A site like https://www.costarastrology.com/natal-chart/ is helpful because it creates a basic circular birth chart and organizes your planets and signs into an easy-to-read table.
- While you can learn the complicated process of calculating an astrology chart by hand, it's much easier to let an online calculator do the work.
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Optionally, you can also create a synastry chart online. Synastry involves comparing two birth charts by laying one chart over the other. Professional astrologers commonly use synastry charts to calculate compatibility between two people. However, while synastry can give you a deeper look at compatibility, it's not needed to compare astrology charts.
- On synastry charts, the inner ring of the synastry chart reflects one person's signs and planets, and the outer circle shows how the other person's planets match up.
- Synastry charts can be pretty complicated, but sites like https://astro-charts.com/tools/new/synastry/ can calculate the chart for you.

Method 2

Method 2 of 3:

Exploring Planets and Aspects

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An astrology chart represents the sky at the moment of your birth. It shows each planet's exact location and which constellation—AKA, zodiac sign—they occupied when you were born. Every planet rules a different facet of life, and the associated zodiac signs explain your behavior in those areas. Thus, you can measure compatibility by comparing your and your crush's zodiac signs for each planet.
- There are 10 planets total in astrology, divided into "inner" and "outer" planets.
- The Sun, Moon, Mercury, Venus, and Mars are inner planets ruling personality and daily life. Zodiac signs connected to these planets are the ones you'll look at most for compatibility.
- Jupiter, Saturn, Uranus, Neptune, and Pluto are outer planets ruling more significant trends and even whole generations. Generally, the outer planets are less critical when considering compatibility.^{[2]
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Planetary aspects describe the angles that planets form to each other. To find an aspect, all you have to do is look at the two planets you're comparing. Once you know what each planet's zodiac sign is, count the number of signs between them—and this will tell you what aspect they form. Your compatibility can be judged on the aspects your planets form, and which ones are hard or soft.^{[3]
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- The key aspects in astrology are conjunctions, sextiles, trines, oppositions, and squares.^{[4]
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Oppositions and squares are hard aspects. This means they bring challenges to a relationship. A square aspect is two planets at a 90-degree angle, or 3 signs apart, which means tension between your signs; it's intense, but not necessarily bad. Opposing aspects are two planets that fall on opposite sides of the zodiac wheel. It means there can be some dissonance in your relationship and how you think.
- Pisces is three signs away from Sagittarius on the zodiac. Therefore, if your Moon is in Pisces and your crush's Sun is in Sagittarius, they form a square aspect.
- Aries is opposite Libra on the zodiac wheel; therefore, a Mercury in Aries and a Venus in Libra form an opposition.
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Sextile and trine are soft aspects, indicating harmony and positivity. A sextile aspect refers to signs at a 60-degree angle, or two signs apart. They're never from the same element or modality (cardinal, mutable, and fixed), but they are great news for compatibility!^{[5]
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Research source} A trine aspect means that your planets are at a 120-degree angle, or four signs apart. It's usually considered the strongest of the soft aspects.
- Leo and Gemini are two signs apart, forming a comfortable and easy connection. If your Sun is in Leo and theirs is in Gemini, your Suns are sextile.
- Trines are essentially formed by different signs of the same element. If your Sun sign is in Sagittarius and your crush's Sun is in Aries, they form a trine aspect.
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Conjunctions can be hard or soft but are usually a good thing. When two or more planets are 0 degrees apart, they're conjunct. Essentially, it means your signs are the same. Conjunctions can be interpreted in a positive or negative light depending on the nature of the signs involved and the energy of the conjunct planets.^{[6]
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- For example, if you and your crush both have Capricorn Suns, it means they're conjunct. That's also a soft (positive) aspect to have since it means you'll relate to one another on a fundamental level.

Method 3

Method 3 of 3:

Comparing Aspects for Compatibility

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Common elements and zodiac signs indicate a harmonious pairing. Generally, you can tell if a relationship is solid (in astrology terms) by seeing what elements and signs dominate a couple's birth chart. Signs of the same element tend the be the best matches, but signs from complementary elements also make great pairings.
- For instance, if both birth charts both have a lot of water signs (those being Pisces, Cancer, and Scorpio), then it's fair to say you and your crush have a lot in common. Signs of the same element form trines and conjunctions!
- Earth and water signs are complementary, as are air and fire. In terms of aspects, that's why all sextiles are fire/air and earth/water pairings. If you have lots of fire signs in your birth chart and your crush has lots of air signs, you'll get along like a house on fire!
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Compare Sun signs to see how your basic personalities match. This is the most common sign that people use to determine compatibility, and it's helpful to a point. Your Sun sign is the highest expression of your true self, after all, and reflects the energy that you show to the rest of the world.^{[7]
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Expert Source

Angel Eyedealism
Astrologer & Performance Artist
Expert Interview. 8 December 2021.} If your Sun signs form a positive aspect, that means you'll have an easy time getting along.
- For example, Suns in Taurus and Cancer are compatible because they're complementary elements and sextile to each other.
- It's easy to compare Sun signs, but your personality goes deeper than that. If your Sun signs aren't compatible, do some digging; there's likely compatibility elsewhere in your birth charts.
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A compatible Mercury aspect means that communication is your strong suit. Since it's essential to any relationship and Mercury is the ruling planet of communication, this is a fantastic connection to have with your significant other. Look at your Mercury signs and determine the aspect that they form; if it's positive, then it'll be smooth sailing in day-to-day interactions with each other.
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You have fantastic long-term potential with complementary Saturn aspects. While most of your compatibility is determined through looking at your inner planets, an outer planet like Saturn can actually be helpful! It rules your sense of commitment and the way you approach hardships, so if your Saturn signs connect, it means you'll be dedicated to one another and overcome struggles seamlessly as a team.
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Positive Sun-Moon aspects lead to a supportive connection. The Moon sign is just as important as the Sun since it relates to your inner feelings and emotional core. Compare your Sun sign to your love interest's Moon sign and vice versa to check compatibility. If your signs connect, it means you'll each have an innate understanding of each other's emotional needs.
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Compatible Sun-Venus signs spell potential for a serious relationship. Check and see if your Venus sign compliments your significant other's Sun. If there's a connection, it means that your romantic values (Venus) will be reflected in their basic personality (Sun). You won't have to think hard to understand what each of you wants in a relationship because it will come to you instinctively.
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A Moon-Venus connection indicates a mutual sense of security. Because the Moon represents your inner self and Venus is your approach to romance, the love between you and your partner will feel comfortable and stable. Check each Moon-Venus aspect and look for compatibility between your signs.
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Look at each of your Venus-Mars aspects. Venus rules love, and Mars rules passion.^{[8]
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Angel Eyedealism
Astrologer & Performance Artist
Expert Interview. 8 December 2021.} When those planets connect, it means you've got a lot of chemistry! Remember that any aspect can be positive here: a trine or sextile aspect means that you'll share a sweet-natured romance. At the same time, a square or opposition can spell a more heated tension (and intense attraction) between you.
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Not everything on your charts need to line up! Don't be disheartened if some of your signs form squares and oppositions instead of sextiles and trines. There are a lot of different aspects to look at when determining compatibility, and even just a couple of positive aspects can predict a long and loving relationship.
- For example: even if you compare two charts and find squares or oppositions in most aspects, but discover a trine in your Venus and sextile Moons, that's an overall positive reading.
- While square aspects mean tension, knowing where that tension can occur in theory will help you work through it in reality.
- Opposing aspects mean you may have to put effort into understanding one another, but remember that opposites also attract big time!

Expert Q&A

Question

How do I find out what my moon sign is?

Angel Eyedealism
Astrologer & Performance Artist
Angel Eyedealism is an Astrologer and Performance Artist based in the Lower East Side of Manhattan. With nearly three decades of astrology experience, Angel specializes in relocation astrology and astrocartography. Eyedealism has been featured in numerous media outlets such as Vogue, Cosmopolitan, The Atlantic, The Washington Post, Refinery29, NBC, MTV, Showtime, and Bravo. Angel aims to help others through a straightforward, kind, and humorous astrological lens, utilizing her entertainment and singing skills for performance art astrology readings.

Angel Eyedealism

Astrologer & Performance Artist

Expert Answer

Consult an ephemeris—that's a list of all the planetary placements that goes back for centuries. You can also use an online app, or speak with an astrologer.