Compatibility Analysis

Romantic compatibility analysis:

Synastry & Relationship Astrology

On our main Synastry page, we offered an overview of considerations for compatibility. On our House Overlays page, we examine person A's planets in person B's houses, and vice versa. On our More on Synastry page, we explore more Synastry details and compatibility factors. On our Synastry Books Compared page, we reveal our favorite books on relationship astrology, and why we like them. On this page, we will explore some key interchart aspects and positions to look for when comparing two charts, from a romantic perspective.

It is easy to feel overwhelmed when we attempt to compare two natal charts of people involved in a romantic relationship or of a potential relationship. We suddenly have two charts to analyze instead of one, comparisons to make, and many astrologers (including myself) will draw up a composite chart as well.

Some astrologers have put together score sheets that help students of astrology organize their findings and come to an overall "judgment". I have always skipped past score sheets, simply because it didn't feel right for me to tally up points for and against compatibility. Similarly, I am not overly fond of score sheets that weigh such things as elements and qualities, preferring to work in a more intuitive manner.

For example, most chart calculation programs will tally up the number of planets placed in the elements (Fire, Earth, Air, and Water) for a given natal chart. With my natal chart, I would get the following tally: Fire 5, Earth 3, Air 1, Water 2. That would make me largely a Fire-Earth personality. I cannot agree with that! For one thing, although I do have two personal planets in Fire (Venus and Mars), and my Ascendant is Fire as well, the other two Fire points come from Jupiter and Saturn in Fire signs (these are not personal planets). I do not have a predominantly Fire personality. People who know me wouldn't consider me as fiery, except perhaps those who know me intimately (Venus and Mars in fire). Although my Ascendant is Fire, Saturn is conjunct the Ascendant, which has the effect of toning down the fire element, and (in my opinion) adds an Earthy emphasis. Some astrologers will assign more points to the Sun, Moon, and Ascendant, which makes a lot of sense. If I gave these three points 2 points each, and the others 1, I would arrive at this tally: Fire 6, Earth 4, Air 1, Water 3. Not much different! I still would be considered a Fire-Earth personality. Factors such as Uranus conjunct the Sun, Saturn rising, Moon in a water sign conjunct the Ascendant from the 12th house—all of which have a strong influence on the personality—are not incorporated into these tallies.

However, I have come to the conclusion that, if taken with a grain of salt, score sheets can be useful for organizing one's thoughts and for honing in on the more "weighty" factors in an analysis.

Consequently, I have devised my own romantic compatibility "score sheet", but I feel the need to list all sorts of disclaimers at the same time! We should never underestimate our intuition when we read charts. By intuition, I mean the general "feel" we get from a chart we are studying.

There are always exceptions to the rules. In fact, there are no set "rules" in the first place—there are only systems. Every astrologer has to be taught somehow, whether it is through face-to-face instruction or through books, but most will use the systems they were taught and refine them, ending up with their own modified systems.

What follows are a large number of compatibility factors in synastry (that is, comparison of one chart to another chart), weighted with numerical values 4, 3, 2, 1, -1, -2, -3, and -4. Note that the following aspects and positions are NOT those found in individual natal charts. They are chart-to-chart (or interchart) aspects and positions.

None of these weights are absolute. I offer these as a general guideline only. For example, Mercury conjunct, sextile, or trine Mercury is given a weight of +2. However, it may be more relevant when the individuals involved are Mercurial by nature, or have Mercury in the 7th house (indicating that Mercury is especially important in relationships to that particular person). Perhaps for a Mercurial person, it should be assigned more weight. There are other factors that are important that are not listed here. What of an overlay of Venus in the other's 5th house, for example? I have not included everything here—if I did, the list would be even longer than it already is (!) and perhaps unwieldy.

Note: You do not have to actually tally up points. The points definitely help in that they assign relative weights to different factors, but another way of approaching this system is to take note of how many positions fall in each category. Note the following:

It is desirable to have:

At least one combination in the Strongest Compatibility (weight 4) category
At least 4 or 5 in the Very Strong Compatibility (weight 3) category
Zero or at most 1 in the Red Alert (weight -4) category
At most 3 in the weight -3 category
At least 3 but no more than 7 in the weight -2 category [Note that it IS desirable to have some challenging aspects in a relationship.]

Remember that some categories will be counted twice, when couples have similar aspects or positions going both ways. For example, my Sun might sextile your Mars, and your Sun might trine my Mars. Therefore we get 3 points two times over.

This list is provided twice, in two different ways. The first list organizes the aspects and positions by weight, and the second list is one that is arranged more intuitively so that it is easier to use if you are going to actually tally up scores. (Some of the items are clickable for an interpretation).

Strongest Compatibility in Synastry (weight 4)

Sun conjunct Descendant 4
Sun conjunct or opposition Vertex 4
Sun conjunct North Node 4
Sun hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 4
Sun in 7th house 4
Moon conjunct Descendant 4
Moon conjunct or opposition Vertex 4
Moon conjunct North Node 4
Moon hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 4
Ascendant conjunct North Node 4

Very Strong Compatibility Factors in Synastry (weight 3)

Sun trine or sextile Sun 3
Sun conjunct, trine, or sextile Moon 3
Sun conjunct Venus 3
Sun trine Venus 3
Sun trine or sextile Mars 3
Sun conjunct, sextile, or trine Jupiter 3
Sun sextile or trine Saturn 3
Sun conjunct, trine, or sextile Chiron 3
Sun conjunct Ascendant 3
Sun conjunct South Node 3
Sun in 1st house 3
Moon conjunct, sextile, or trine Moon 3
Moon conjunct, sextile, or trine Venus 3
Moon sextile or trine Mars 3
Moon conjunct, sextile, or trine Jupiter 3
Moon sextile or trine Saturn 3
Moon conjunct, trine, or sextile Chiron 3
Moon conjunct Ascendant 3
Moon sextile or trine Ascendant 3
Moon conjunct IC 3
Moon conjunct South Node 3
Moon in 7th house 3
Moon in 1st house 3
Mercury conjunct, sextile, or trine Jupiter 3
Venus conjunct, sextile, trine, or opposition Venus 3
Venus conjunct, sextile, or trine Mars 3
Venus conjunct Jupiter 3
Venus sextile or trine Saturn 3
Venus conjunct, trine, or sextile Chiron 3
Venus conjunct Ascendant 3
Venus conjunct Descendant 3
Venus hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 3
Venus in 7th house 3
Mars hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 3
Ascendant conjunct South Node 3
Ascendant hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 3
Ascendant in 7th house 3
Vertex hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 3
Nodes of the Moon conjunct IC/MC 3

Good Compatibility Factors in Synastry (weight 2)

Sun opposition Sun 2
Sun opposition Moon 2
Sun conjunct Mercury 2
Sun sextile or trine Mercury 2
Sun sextile Venus 2
Sun conjunct Mars 2
Sun sextile or trine Uranus 2
Sun sextile or trine Ascendant 2
Sun conjunct IC 2
Sun sextile or trine Nodes of the Moon 2
Sun square Nodes of the Moon 2
Moon conjunct, sextile, or trine Mercury 2
Moon sextile or trine Uranus 2
Moon sextile or trine Neptune 2
Moon sextile or trine Pluto 2
Moon trine or sextile Nodes of the Moon 2
Moon square Nodes of the Moon 2
Mercury sextile, conjunct, or trine Mercury 2
Mercury conjunct, sextile, or trine Venus 2
Mercury sextile or trine Mars 2
Mercury conjunct the Ascendant 2
Mercury conjunct the Descendant 2
Mercury conjunct IC or MC 2
Venus square or opposition Mars 2
Venus trine or sextile Jupiter 2
Venus conjunct Saturn 2
Venus sextile or trine Uranus 2
Venus conjunct Neptune 2
Venus trine or sextile Neptune 2
Venus conjunct, trine or sextile Pluto 2
Venus sextile or trine Ascendant 2
Venus conjunct IC or MC 2
Venus conjunct or opposition Vertex 2
Venus in aspect to Nodes of the Moon 2
Venus in 1st house 2
Mars conjunct, sextile, or trine Mars 2
Mars in aspect to Jupiter 2
Mars conjunct, trine, or sextile Pluto 2
Mars conjunct, sextile, or trine the Ascendant 2
Mars conjunct the Descendant 2
Mars conjunct or opposition Vertex 2
Jupiter in aspect to Jupiter 2
Jupiter conjunct the Ascendant 2
Jupiter conjunct the Descendant 2
Jupiter conjunct or opposition the Vertex 2
Jupiter in 7th house 2
Ascendant sextile or trine Ascendant 2
Ascendant opposition Ascendant 2
Ascendant trine or sextile Nodes of the Moon 2
Ascendant square Nodes of the Moon 2
Vertex conjunct either Node of the Moon 2

Helpful Compatibility Factors in Synastry (weight 1)

Sun conjunct Sun 1
Sun square or opposition Jupiter 1
Sun sextile or trine Neptune 1
Sun conjunct, sextile or trine Pluto 1
Moon opposition Moon 1
Moon square or opposition Venus 1
Moon square or opposition Jupiter 1
Moon conjunct Neptune 1
Moon conjunct Pluto 1
Mercury square or opposition Jupiter 1
Mercury sextile or trine Saturn 1
Mercury in aspect to Uranus 1
Mercury in aspect to Neptune 1
Mercury in aspect to Pluto 1
Mercury sextile or trine Ascendant 1
Mercury conjunct or opposition Vertex 1
Mercury in aspect to Nodes of the Moon 1
Venus square Venus 1
Venus square or opposite Jupiter 1
Venus conjunct Uranus 1
Venus square Ascendant 1
Mars sextile or trine Saturn 1
Mars sextile or trine Neptune 1
Mars conjunct, sextile, or trine Uranus 1
Mars in aspect to Nodes of the Moon 1
Jupiter conjunct, sextile, or trine Saturn 1
Jupiter in aspect to Uranus 1
Jupiter conjunct, sextile, or trine Neptune 1
Jupiter conjunct, trine or sextile Pluto 1
Jupiter sextile, trine, or square Ascendant 1
Jupiter in aspect to the Nodes of the Moon 1
Saturn sextile or trine Saturn 1
Saturn sextile or trine Ascendant 1
Pluto conjunct Descendant or Vertex 1
Ascendant conjunct Ascendant 1

Very Challenging Factors in Synastry - Red Alerts (weight -4)

Moon square Saturn -4 Red Alert
Mercury square Mercury -4 Red Alert
Venus square Saturn -4 Red Alert
Mars square or opposition Saturn -4 Red Alert

Challenging Factors in Synastry (weight -3)

Sun square Moon -3
Moon square Moon -3
Moon square Mars -3
Moon conjunct or opposition Saturn -3
Moon square or opposition Neptune -3
Moon square or opposition Pluto -3
Mercury square or opposition Neptune -3
Venus opposition Saturn -3
Venus square or opposition Neptune -3
Mars conjunct Saturn -3
Mars square or opposition Pluto -3
Uranus conjunct Descendant or Vertex -3

Somewhat Challenging Factors in Synastry (weight -2)

Minor Challenges in Synastry (weight -1)

Sun square or opposition Mercury -1
Sun square or opposition Venus -1
Sun conjunct, square or opposition Uranus -1
Moon conjunct Mars -1
Moon conjunct Uranus -1
Mercury square or opposition Venus -1
Mercury conjunct Mars -1
Mercury square Ascendant -1
Mars square Ascendant -1
Jupiter square or opposition Saturn -1
Jupiter square or opposition Neptune -1
Jupiter square or opposition Pluto -1
Saturn square or opposition Saturn -1

Printer-Friendly version of the above categories.

This exact same list is offered below in a more logical sequence for those willing to tally up the points:

Sun conjunct Sun 1
Sun trine or sextile Sun 3
Sun square Sun -2
Sun opposition Sun 2
Sun conjunct, trine, or sextile Moon 3
Sun square Moon -3
Sun opposition Moon 2
Sun conjunct Mercury 2
Sun sextile or trine Mercury 2
Sun square or opposition Mercury -1
Sun conjunct Venus 3
Sun trine Venus 3
Sun sextile Venus 2
Sun square or opposition Venus -1
Sun conjunct Mars 2
Sun trine or sextile Mars 3
Sun square or opposition Mars -2
Sun conjunct, sextile, or trine Jupiter 3
Sun square or opposition Jupiter 1
Sun sextile or trine Saturn 3
Sun conjunct, square or opposition Saturn -2
Sun sextile or trine Uranus 2
Sun conjunct, square or opposition Uranus -1
Sun conjunct, square, or opposition Neptune -2
Sun sextile or trine Neptune 1
Sun conjunct, sextile or trine Pluto 1
Sun square or opposition Pluto -2
Sun conjunct, trine, or sextile Chiron 3
Sun conjunct Ascendant 3
Sun sextile or trine Ascendant 2
Sun square Ascendant -2
Sun conjunct Descendant 4
Sun conjunct IC 2
Sun conjunct or opposition Vertex 4
Sun conjunct North Node 4
Sun conjunct South Node 3
Sun sextile or trine Nodes of the Moon 2
Sun square Nodes of the Moon 2
Sun hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 4
Sun in 7th house 4
Sun in 1st house 3

Moon conjunct, sextile, or trine Moon 3
Moon square Moon -3
Moon opposition Moon 1
Moon conjunct, sextile, or trine Mercury 2
Moon square or opposition Mercury -2
Moon conjunct, sextile, or trine Venus 3
Moon square or opposition Venus 1
Moon conjunct Mars -1
Moon sextile or trine Mars 3
Moon square Mars -3
Moon opposition Mars -2
Moon conjunct, sextile, or trine Jupiter 3
Moon square or opposition Jupiter 1
Moon sextile or trine Saturn 3
Moon square Saturn -4
Moon conjunct or opposition Saturn -3
Moon conjunct Uranus -1
Moon sextile or trine Uranus 2
Moon square or opposition Uranus -2
Moon conjunct Neptune 1
Moon sextile or trine Neptune 2
Moon square or opposition Neptune -3
Moon conjunct Pluto 1
Moon sextile or trine Pluto 2
Moon square or opposition Pluto -3
Moon conjunct, trine, or sextile Chiron 3
Moon conjunct Ascendant 3
Moon sextile or trine Ascendant 3
Moon square Ascendant -2
Moon conjunct Descendant 4
Moon conjunct IC 3
Moon conjunct or opposition Vertex 4
Moon conjunct North Node 4
Moon conjunct South Node 3
Moon trine or sextile Nodes of the Moon 2
Moon square Nodes of the Moon 2
Moon hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 4
Moon in 7th house 3
Moon in 1st house 3

Mercury sextile, conjunct, or trine Mercury 2
Mercury square Mercury -4
Mercury opposition Mercury -2
Mercury conjunct, sextile, or trine Venus 2
Mercury square or opposition Venus -1
Mercury conjunct Mars -1
Mercury sextile or trine Mars 2
Mercury square or opposition Mars -2
Mercury conjunct, sextile, or trine Jupiter 3
Mercury square or opposition Jupiter 1
Mercury conjunct, square, or opposition Saturn -2
Mercury sextile or trine Saturn 1
Mercury in aspect to Uranus 1
Mercury sextile or trine Neptune 1
Mercury square or opposition Neptune -3
Mercury in aspect to Pluto 1
Mercury conjunct the Ascendant 2
Mercury sextile or trine Ascendant 1
Mercury square Ascendant -1
Mercury conjunct the Descendant 2
Mercury conjunct IC or MC 2
Mercury conjunct or opposition Vertex 1
Mercury in aspect to Nodes of the Moon 1

Venus conjunct, sextile, trine, or opposition Venus 3
Venus square Venus 1
Venus conjunct, sextile, or trine Mars 3
Venus square or opposition Mars 2
Venus conjunct Jupiter 3
Venus trine or sextile Jupiter 2
Venus square or opposite Jupiter 1
Venus conjunct Saturn 2
Venus sextile or trine Saturn 3
Venus square Saturn -4
Venus opposition Saturn -3
Venus conjunct Uranus 1
Venus sextile or trine Uranus 2
Venus square or opposition Uranus -2
Venus conjunct Neptune 2
Venus trine or sextile Neptune 2
Venus square or opposition Neptune -3
Venus conjunct, trine or sextile Pluto 2
Venus square or opposition Pluto -2
Venus conjunct, trine, or sextile Chiron 3
Venus conjunct Ascendant 3
Venus sextile or trine Ascendant 2
Venus square Ascendant 1
Venus conjunct the Descendant 3
Venus conjunct IC or MC 2
Venus conjunct or opposition Vertex 2
Venus in aspect to Nodes of the Moon 2
Venus hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 3
Venus in 1st house 2
Venus in 7th house 3

Mars conjunct, sextile, or trine Mars 2
Mars square or opposition Mars -2
Mars in aspect to Jupiter 2
Mars square or opposition Saturn -4
Mars conjunct Saturn -3
Mars sextile or trine Saturn 1
Mars conjunct, sextile, or trine Uranus 1
Mars square or opposition Uranus -2
Mars sextile or trine Neptune 1
Mars conjunct, square, or opposition Neptune -2
Mars conjunct, trine, or sextile Pluto 2
Mars square or opposition Pluto -3
Mars conjunct, sextile, or trine the Ascendant 2
Mars square Ascendant -1
Mars conjunct the Descendant 2
Mars conjunct or opposition Vertex 2
Mars in aspect to Nodes of the Moon 1
Mars hard aspect (conjunct, semi-square, square, opposition) Sun/Moon midpoint 3

Jupiter in aspect to Jupiter 2
Jupiter conjunct, sextile, or trine Saturn 1
Jupiter square or opposition Saturn -1
Jupiter in aspect to Uranus 1
Jupiter conjunct, sextile, or trine Neptune 1
Jupiter square or opposition Neptune -1
Jupiter conjunct, trine or sextile Pluto 1
Jupiter square or opposition Pluto -1
Jupiter conjunct the Ascendant 2
Jupiter sextile, trine, or square Ascendant 1
Jupiter conjunct the Descendant 2
Jupiter conjunct or opposition the Vertex 2
Jupiter in aspect to the Nodes of the Moon 1
Jupiter in 7th house 2

Saturn sextile or trine Saturn 1
Saturn square or opposition Saturn -1
Saturn conjunct, square or opposition Ascendant -2
Saturn sextile or trine Ascendant 1
Saturn conjunct or opposition Vertex -2
Saturn conjunct or square Nodes of the Moon -2

Uranus conjunct Descendant or Vertex -3

Neptune conjunct Descendant, Ascendant, or Vertex -2

Pluto conjunct Descendant or Vertex 1

Ascendant conjunct Ascendant 1
Ascendant sextile or trine Ascendant 2
Ascendant square Ascendant -2
Ascendant opposition Ascendant 2
Ascendant conjunct North Node 4
Ascendant conjunct South Node 3
Ascendant trine or sextile Nodes of the Moon 2
Ascendant square Nodes of the Moon 2
Ascendant hard aspect (conjunction, semi-square, square, opposition) Sun/Moon midpoint 3
Ascendant in 7th house 3

Vertex hard aspect (conjunction, semi-square, square, opposition) Sun/Moon midpoint 3
Vertex conjunct either Node of the Moon 2

Nodes of the Moon conjunct IC/MC 3

Printer-friendly version of the above list of compatibility factors.

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Some scoring examples:

A couple that lasted 10 months, the last 5 months of which were very challenging, no commitment: +39 -28, for a score of 11. One Weight 4, two Weight -4 factors.
A couple married for 15 years, difficult divorce: +56 -20, for an overall score of +36. Four Weight 4, one Weight -4 factors.
A couple married for 2 years, easy divorce: +26 -29, for a score of -3. No Weight 4 factors, one Weight -4 factor.
Paul Newman and Joanne Woodward, long-lasting marriage: +82 -23, for a score of +59. Two Weight 4 factors, fourteen Weight 3 factors, two Weight -3 factors, one Weight -4 (Red alert) factor.

Generally, the higher the positive score, the more that binds the couple together in the long term.

However, even many Weight 4 factors do not always save a couple from divorce (as can be seen with example 2). When numbers are high in the + category, and the couple does eventually break up, the more potential for a challenging break up, perhaps because the bond was strong in the first place.

For example, if we compare the scores of the two divorced couples (examples 2 and 3), even though there was a higher negative score for the couple in example 3, there was a weak showing in the positive score as well. This likely accounts for the easy divorce—it was a quick marriage and easy divorce, as if the couple pretty much accepted that it was perhaps a "mistake" in the first place, so there were few hard feelings.

Example 4 is a famous couple often used as an example in relationship astrology. One of the reasons is that the birth data is accurate, and another is because the couple's marriage has been long-standing, which isn't very common with celebrities. Here we see an extremely high positive score, and a rather high negative score. They have two Weight 4 (Strongest Compatibility) factors, and a whopping fourteen Weight 3 (Very Strong Compatibility) factors. They have one Weight 4 (Red Alert) factor, and a rather low number of Weight -3 (Challenging) factors.

See our main Synastry hub page and scroll down to the bottom for links to all of our Synastry articles.

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Compatibility Analysis

Romantic compatibility analysis:

Synastry & Relationship Astrology

Strongest Compatibility in Synastry (weight 4)

Very Strong Compatibility Factors in Synastry (weight 3)

Good Compatibility Factors in Synastry (weight 2)

Helpful Compatibility Factors in Synastry (weight 1)

Very Challenging Factors in Synastry - Red Alerts (weight -4)

Challenging Factors in Synastry (weight -3)

Somewhat Challenging Factors in Synastry (weight -2)

Minor Challenges in Synastry (weight -1)

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