Free compatibility reading
How to check two people's compatibility with a horoscope
"How compatible am I with that person?" — In astrology, a technique called synastry, which overlays two people's horoscopes, lets you analyze compatibility in love, friendship, and work from many angles. We explain how genuine compatibility readings work — on a completely different level from sun-sign-only "star sign horoscopes."
What is a synastry chart?
Synastry is a compatibility technique that overlays two people's natal charts and analyzes the angles (aspects) between their planets. Rather than just sun-sign compatibility, it reads a relationship from many angles, such as the following.
☀️Sun × Sun
How aligned your core values and life direction are
🌙Moon × Moon
Emotional compatibility and how secure you feel together
💕Venus × Mars
Romantic and sexual attraction, and romance compatibility
🗣️Mercury × Mercury
Compatibility of communication styles
🌙☀️Moon × Sun
Marriage compatibility and the harmony of emotion and will
💫Venus × Venus
Matching aesthetic sense and preferences in expressing love
Why sun-sign-only compatibility readings fall short
The "compatibility between sign X and sign Y" you often see in magazines and on the web is judged on sun signs alone. In reality, though, compatibility involves all 10 planets.
Example: a couple whose "suns are incompatible" yet it works out
Even if the sun signs are Aries × Cancer (Fire × Water, an iffy match)...
- ・Same moon sign → deep emotional resonance
- ・Venus and Mars at a favorable angle → strong romantic attraction
- ・Mercuries in conjunction → conversation is simply fun
In this way, viewed as a whole, they can turn out to be a highly compatible couple.
Basic compatibility by the four elements
The 12 signs are classified into the four elements: fire, earth, air, and water. First, let's check rough compatibility by element combination.
🔥🔥Fire × Fire (Aries, Leo, Sagittarius)
★★★★☆A passionate, energetic relationship. Exciting but prone to clashes. The key is respecting each other's independence.
🔥💨Fire × Air (Aries, Leo, Sagittarius × Gemini, Libra, Aquarius)
★★★★★One of the best matches. Air fans the fire, and they spur each other's growth. Communication is lively too.
🔥🌍Fire × Earth (Aries, Leo, Sagittarius × Taurus, Virgo, Capricorn)
★★★☆☆Fire's impulsiveness and Earth's caution are polar opposites. If they learn from each other they can be complementary, but differing values make clashes likely.
🔥💧Fire × Water (Aries, Leo, Sagittarius × Cancer, Scorpio, Pisces)
★★☆☆☆Fire is put out by water, and water is evaporated by fire. Emotional understanding is hard, but it can also be a match with deep lessons.
🌍💧Earth × Water (Taurus, Virgo, Capricorn × Cancer, Scorpio, Pisces)
★★★★★A harmony of stability and deep emotion. They give each other a sense of security and easily build a lasting relationship.
💨💧Air × Water (Gemini, Libra, Aquarius × Cancer, Scorpio, Pisces)
★★☆☆☆Mismatches between intellect and emotion arise easily. It is important to understand each other's differing communication styles.
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Try it free nowHow to do a compatibility reading on aiAstro (free)
Prepare both people's birth data
Have the birth date, birth time, and birthplace ready for both people. The birth time is needed to calculate the moon sign accurately.
Create a synastry chart on aiAstro
From the top page, choose synastry (compatibility) mode and enter both people's data.
AI explains your overall compatibility
AI analyzes the aspects of major planets such as the Sun, Moon, Venus, and Mars, and explains your love, communication, and long-term compatibility in detail.
Aspects (planetary angles) worth knowing
What matters most in synastry are the angles (aspects) formed between the two people's planets.
Conjunction (0°)
Merging and emphasis. The two energies fuse together. The most powerful compatibility point.
Trine (120°)
Harmony and a natural flow. An easy relationship where you understand each other without effort.
Square (90°)
Tension and challenge. A relationship with lots of friction that can spark growth.
Opposition (180°)
Attraction and repulsion. A magnetic appeal, but also clashes of values.
Frequently asked questions
Q. Can you read compatibility even without the other person's birth time?
Yes. Even without a birth time, the compatibility of major planets such as the Sun, Venus, and Mars can be analyzed. However, the moon sign and overlapping houses require a birth time, so enter what you can.
Q. Can you also read compatibility with friends or family?
Of course. Synastry can be used not only for romance but also for analyzing compatibility in friendships, parent-child relationships, and business partnerships. aiAstro provides explanations tailored to the type of relationship.
Q. What should I do if the result says we're incompatible?
Astrological compatibility is not 'destiny' but a 'tendency.' Even with many squares or oppositions, it can be read as 'a relationship in which you can grow together.' AI's explanation also tells you points for improvement.
Have AI read your compatibility for free
Beyond what sun signs alone can show, all the way to Moon, Venus, and Mars compatibility. AI creates a synastry chart and interprets your relationship from many angles.
Check your compatibility free now (no login required)