Zodiac sign compatibility in love and desire: what the element chart misses

The element chart compares Sun signs and says nothing about the Venus–Mars link that astrology ties to attraction. Astrological practice groups Sun signs into elements, calling couples "compatible" if their elements are in tune—meaning they share an element or form allied pairs like fire with air or earth with water. Every other combination is considered tense. A test on a million random couples shows exactly half fit the "compatible" group. Astrologers measure attraction differently, focusing on a link, which means comparing a planet of one person with a planet of the other. For desire, they look at how one person's Venus aligns with the other's Mars. It comes out the same in "compatible" and "incompatible" couples. Both halves of the link are in tune for about one couple in four, at 24.9% and 25.2%. Across all 78 possible Sun sign combinations, this rate shifts only between 23.7% and 26.0%. Our measurement compares two astrological methods with each other, saying nothing about real attraction between people.

How the element compatibility chart works

The twelve zodiac signs divide into four elements, with three signs in each category:

Tradition says that signs of the same element understand each other easily. Fire and air act as allies, since air feeds fire, while earth and water form another alliance. Out of the 78 possible pairs of signs, these rules produce 42 combinations that are in tune and 36 that are tense.

The chart uses the Sun sign because it needs nothing more than a date of birth. In astrology, the Sun represents will, character, and personal goals. Comparing Sun signs is traditionally thought to show whether two people share a similar pace of life and communication style. When applying this method to attraction, practitioners are looking at astrological points that were never meant to describe passion.

What an astrologer looks at for attraction

In astrology, attraction depends on the positions of Venus and Mars. Traditionally, Venus indicates what draws a person in and what they value in intimacy, while Mars represents how they act, show desire, and take the lead. Comparing these points in a couple requires a crosswise approach, looking at one person's Venus against the other's Mars, and then reversing the order. Whenever the elements of these planets match, astrological theory suggests that one person's preferences align with how the other behaves.

Within its "Chemistry" section, our couple compatibility calculator examines four specific links: the first person's Venus with the second person's Mars, the first person's Mars with the second person's Venus, the two Mars placements, and the two Moons, which represent feelings and habits. Each link is marked "in tune" or "tense" by the same element rule.

For one person, we have a name of our own. The element of desire is the pairing of your Venus element and your Mars element: what draws you in and how you act. There are sixteen pairings. You can check yours using our Venus and Mars calculator.

Why your Sun sign says almost nothing about Venus and Mars

Venus remains close to the Sun in the sky, never moving more than about 47 degrees away. This proximity means Venus always sits in the Sun's sign, the next sign, or two signs away. Signs next door and two signs away always belong to a different element. Venus shares the Sun's element only when it is in the same sign, which happens for 23.7% of people. For everyone else, the planet falls into one of the other three elements. Sun elements say nothing about Venus and Mars, as their positions follow entirely different rules.

Mars completes a journey around the zodiac in roughly two years, meaning it can occupy any sign regardless of the Sun's position. The Moon moves into the next sign roughly every two to three days.

Because of these varying orbits, the Sun sign barely lets you predict how the links will turn out. Using the basic element method means comparing the astrological point for character, which yields almost no information about the points governing attraction.

What a million couples showed

We selected 100,000 random birth moments between 1950 and 2008 to examine these patterns. After calculating the positions of the Sun, Venus, Mars, and the Moon using the Swiss Ephemeris (standard astronomical tables of planetary positions), we generated a million random couples from this dataset. Every pairing received two separate ratings: one based on their Sun signs, and another evaluating their "Chemistry" links using the element rules.

The percentages across the two rows vary by no more than half a percent. In both groups, roughly a quarter of the couples have both Venus–Mars links in tune, another quarter have both tense, and half possess exactly one matching link. These proportions match the mathematical probability of Venus and Mars elements combining at random, showing no influence from the Sun's position.

The element compatibility chart, pair by pair

Figures across all ten rows align within the measurement's margin of error, which sits at about half a percent for the element rows. Popular horoscopes often call a fire–air couple "ideal" and an air–water pairing "impossible", but they present the exact same picture of attraction.

Couples of the same sign: Taurus and Taurus, Leo and Leo

Couples of the same sign deserve a separate look. By the chart they are always in tune, since they share an element. In our measurement they do not stand out from the rest.

Statistical variations between these signs remain within the margin of error, which is about one percent for the same-sign rows. Each row in this table draws from a sample of about seven thousand couples. As all the measurements show, Sun elements say nothing about Venus and Mars.

What studies of real marriages found

Our analysis specifically tests whether two different astrological methods produce agreeing results, while other researchers have used massive datasets to examine whether any of these methods reflect real life.

The British sociologist David Voas published a working paper in 2007 comparing the Sun signs of spouses from the 2001 census of England and Wales, which included more than ten million marriages. He concluded that "astrological sign has no impact on the probability of marrying – and staying married to – someone of any other sign." Swedish demographers Jonas Helgertz and Kirk Scott conducted a similar test in 2020 on Swedish registers from 1968 to 2001. They found no consistent evidence that "compatible" couples marry more often or divorce less.

Scientific tests of personality derived from astrological charts have yielded similar outcomes. The physicist Shawn Carlson published a double-blind experiment in Nature in 1985, where astrologers failed to match birth charts with personality profiles at a rate higher than pure chance. Researchers Geoffrey Dean and Ivan Kelly conducted a study in 2003 comparing 2,101 people born in London during one week of March 1958, on average about five minutes apart. They observed none of the behavioral similarities that astrological theory predicts. Studies of real marriages found no link between astrological compatibility and how relationships turn out; astrology can be used as a language for talking about yourself and your couple.

How to look at your own couple

To go beyond Sun signs, you need the Venus, Mars and Moon of both partners. Our couple compatibility calculator determines these points using two birth dates, displaying the four specific "Chemistry" links. Adding an exact birth time increases the accuracy of this reading, since the Moon moves into the next sign roughly every two to three days, making its position uncertain without a time.

Exploring your own chart provides another starting point. The Venus and Mars calculator reveals your personal Venus, Mars, Moon, and element of desire. How an astrologer compares the Venus, Mars and Moon of two people in more detail is covered in Venus and Mars in synastry.