How to read a Synastry Chart

The Synastry chart is one of the most important tools to use when assessing compatibility between two people.

The two areas you want to focus on are: house overlays and planetary aspects. 

House overlays

What are houses? Our natal charts are divided up into 12 houses, which each represent a different area of our life:

Here is a breakdown of what each house represents

  • The first house: represents the self, one’s persona, and one’s physical appearance
  • The second house: represents finances, income, material possessions, and self-worth
  • The third house: represents communications, neighbourhood, siblings, learning, local travel
  • The fourth house represents: family, home, past, ancestry, real estate
  • The fifth house represents: children, creativity, romance, fun, leisure
  • The sixth house represents: work, health, coworkers. productivity
  • The seventh house represents: partnership (business and romantic), commitment, sharing, equality
  • The eighth house represents: intimacy, death, transformation, other people’s money, taxes
  • The ninth house represents: travel, higher learning, philosophy, religion
  • The tenth house represents: career, social status, public reputation
  • The eleventh house represents: friends, groups, long-term goals
  • The twelfth house represents: spirituality, solitude, dreams, illusions

What are planets? Our natal charts contain 10 planets. Each represents a different aspect of our personality.

Here is a simple breakdown of what each planet represents

  • Sun: Your basic personality, ego, individuality
  • Moon: your emotional nature and what makes you feel secure
  • Mercury: your communication style and intellectual interests
  • Venus: your love style, what you find beautiful, your personal style
  • Mars: your determination, passion, and sex drive
  • Jupiter: represents expansion, generosity and luck
  • Saturn: represents structure, maturity, commitment, restriction
  • Uranus: represents instability, freedom, unpredictability
  • Neptune: represents illusions, compassion, sensitivity
  • Pluto: represents transformation, obsession, jealousy, power

When comparing two charts, you can see where each person’s planets land in another person’s chart.

For this exercise, let’s look at Kim and Ye’s Synastry. I generated this report on astro.com:

When assessing synastry, check to see where your personal planets fall in the other person’s chart:

  • When someone’s planet falls into one of your houses, they bring the energy of that planet into your house.
  • As you can see from their chart, Ye’s Sun/Jupiter conjunction resides in Kim’s 7th house of partnership and commitment– this is an excellent indication of compatibility and marriage. Ye’s Venus and Mars reside in Kim’s 5th house, which is a great indication of romance and having children.
  • Kim’s Sun resides in Ye’s 4th house of home and family. This is again a great indication of a long-lasting relationship

In a romantic relationship, focus on looking for overlays in the following houses:

  • The first house: another person’s planets falling in your 1st house indicate they are very attracted to you. This is especially powerful if the Sun, Moon, Venus or Mars are in another person’s 1st house, as they are deeply personal planets and increase attraction.
  • The fourth house: represents home, family, and emotions. When someone’s planets fall in your 4th house, they feel like family to you, and you enjoy spending time together at home. This is an indication of wanting to build a home and family together.
  • The fifth house: represents romance, children, and fun, so someone’s planets falling in this house is a great aspect.
  • The seventh house: represents commitment, partnership, equality, etc., so it is obviously a very important house to consider in a synastry chart. If someone’s planets fall in your 7th house, you feel compelled to partner with them. They teach you about compromise, relating, and partnership.
  • The eighth house: represents deep intimacy and bonding, so overlays to this house are very powerful and transformative. These types of relationships are not for the faint of heart, but are ultra intense and sexy (if you like that kind of thing).

Check out my articles on house overlays to learn more:

Sun in the Houses in Synastry

Moon in the Houses in Synastry

Venus in the Houses in Synastry

Mars in the Houses in Synastry

Jupiter in the Houses in Synastry

Saturn in the Houses in Synastry

Uranus in the Houses in Synastry

Neptune in the Houses in Synastry

Pluto in the Houses in Synastry


Planetary Aspects

After looking at house overlays, it is equally important to look at the aspects each person’s planets make the other persons’ planets.

To make things easy, you can generate reports in astro.com by clicking PDF Additional Tables after generating a report.


Reports like these make is easier to assess your planetary overlays with someone:

In this table, you might not recognize the symbols and numbers.

The symbols within the table show the aspect each planet is making to the other. For example, Ye’s Sun is square Kim’s Venus. Check out this article to learn what the symbols represent. The ones you want to focus on most are: Conjunction, Square, Opposition, Trine, and Sextile.

  • Sextiles and trines are nice, harmonious aspects, and are great to see in a chart.
  • Conjunctions are very powerful, and show compatibility between the energies each planet represents.
  • Oppositions can be problematic, but are usually very fascinating. This is a case of ‘opposites attract’.
  • Squares are considered the most problematic, as they cause friction and lack of understanding between the parties.

If you are looking to assess romantic, long-term compatibility with someone, it is very important to look at how each person’s Love planets are aspected in a chart.

Generally, squares from Saturn, Uranus, Neptune, or Pluto are not looked upon very favourably, especially if they make an aspect to someone’s personal planets (Sun, Moon, Mercury, Venus, Mars).

Check out my synastry articles to read about specific aspects.


It is also extremely important to look at how someone’s planets aspect your 7th house ruler. What is your 7th house ruler?

  • If your 1st house is in Aries, the Composite 7th house ruler is Venus
  • If your 1st house is in Taurus, the Composite 7th house ruler is Pluto
  • If your 1st house is in Gemini, the Composite 7th house ruler is Jupiter
  • If your 1st house is in Cancer, the Composite 7th house ruler is Saturn
  • If your 1st house is in Leo, the Composite house ruler is Uranus
  • If your 1st house is in Virgo, the Composite house ruler is Neptune
  • If your 1st house is in Libra, the Composite house ruler is Mars
  • If your 1st house is in Scorpio, the Composite house ruler is Venus
  • If your 1st house is in Sagittarius, the Composite 7th house ruler is Mercury
  • If your 1st house is in Capricorn, the Composite 7th house ruler is the Moon
  • If your 1st house is in Aquarius, the Composite 7th house ruler is the Sun
  • If your 1st house is in Pisces, the Composite 7th house ruler is Mercury

In my opinion, this is the most important planet to look at when considering long-term compatibility.


All in all, synastry aspects and overlays are extremely important to consider in a synastry chart. However, I believe the Composite Chart is more essential to assess long-term compatibility. Click here to read my article on The Best Composite Chart Aspects.