Relationships with room for nuance
Zodiac Compatibility Calculator
This free zodiac compatibility calculator compares two Sun signs through the traditional framework of sign distance, elements and modalities. Choose a sign for each person, or enter a birth date and let the zodiac compatibility calculator find the sign, with a warning when the date falls on a sign-change day. You get a symbolic rating, possible strengths and friction points, and questions worth talking about, never a verdict on a relationship.
Compare two zodiac signs
Pick a Sun sign for each person, or type a birth date and the tool will find the sign for you. The comparison runs in your browser; nothing you enter is sent to the site.
Your compatibility result
Remember: the rating is a symbolic reading of Sun signs only. It is for curiosity and conversation, not a measurement and not a prediction about any relationship.
How this was calculated
How to use the Zodiac Compatibility Calculator
- Choose a Sun sign for Person 1 and Person 2. If you are not sure of a sign, type the birth date under it and the tool fills the sign in.
- Watch for the hint under a date: on sign-change days it shows both possible signs, and you pick the one you know is correct.
- Select Check compatibility. Use Swap people if you want to see the same pair from the other side.
- Read the sign relationship, the element and modality notes, the possible strengths and friction points, and the conversation questions.
What zodiac compatibility means, and what it does not
Zodiac compatibility is the old idea that the relationship between two signs says something about how two people might get on. People ask “are Leo and Sagittarius compatible?” the way they ask about a friend’s new partner: out of curiosity, and a little hope. The tradition offers a vocabulary for that curiosity. It does not offer a forecast.
A Sun sign is one placement out of many in a birth chart. Two people share their Sun sign with roughly one in twelve of everyone alive, so the sign cannot account for a whole personality, let alone a whole relationship. That is why this tool speaks in terms of themes and questions, and why it shows its working.
Method: how two signs are compared
The comparison uses four ideas from traditional Western astrology. Each one is calculated from the position of the signs on the wheel, not looked up in a pre-written list of pairs.
- Sign distance. The number of signs between the two (0 to 6) gives the classical aspect: same sign (conjunction), one apart (semi-sextile), two apart (sextile), three (square), four (trine), five (quincunx) or six (opposition).
- Elements. Fire, Earth, Air and Water repeat around the wheel. Shared elements suggest similar values and emotional language; Fire with Air and Earth with Water are traditionally seen as supportive.
- Modalities. Cardinal signs start things, Fixed signs sustain them and Mutable signs adapt. The mix shows how two people tend to handle change.
- Polarity. Fire and Air are called active and Earth and Water receptive. Matching polarity is read as a similar approach to the world; opposite polarity as complementary.
The symbolic rating comes from the sign relationship alone. These numbers are the SOULTRIANGLE reading convention, chosen to reflect how the tradition ranks the aspects. They are not statistics and they have not been validated against real relationships.
| Sign relationship | Signs apart | Traditional meaning | Rating |
|---|---|---|---|
| Trine | 4 signs (120°) | Same element; the smoothest traditional link | 90 |
| Sextile | 2 signs (60°) | Compatible elements and the same polarity | 80 |
| Conjunction | Same sign (0°) | Mirror image; familiar but doubled | 75 |
| Opposition | 6 signs (180°) | Complementary opposites; attraction and tension | 65 |
| Square | 3 signs (90°) | Same modality, different element; friction and drive | 55 |
| Semi-sextile | 1 sign (30°) | Neighbours with little in common | 50 |
| Quincunx | 5 signs (150°) | No shared element, modality or polarity | 45 |
Worked example: Leo and Sagittarius
Leo is the fifth sign and Sagittarius the ninth, so they are four signs apart, which is 120°. In the framework that is a trine. Both are Fire signs, and Leo is Fixed while Sagittarius is Mutable, which the tradition reads as one who sustains and one who adapts. Both are active signs. A trine scores 90 on the table above, so the tool labels the pair “Strongly harmonious”.
The reading then adds the practical bits: Leo tends to bring warmth and generosity and values appreciation in return; Sagittarius tends to bring optimism and a taste for adventure and values freedom and shared meaning. The shared Fire element makes the match lively, and the tool also notes the usual risk of a trine: comfort can slide into avoiding growth.
Zodiac compatibility chart: all 144 sign pairs
This chart shows the rating for every pair of signs, generated by the same rules as the calculator. Greener cells mean smoother traditional links; paler cells mean more adjustment is expected. Hover over a cell to see the sign relationship.
| ♈ Ari | ♉ Tau | ♊ Gem | ♋ Can | ♌ Leo | ♍ Vir | ♎ Lib | ♏ Sco | ♐ Sag | ♑ Cap | ♒ Aqu | ♓ Pis | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ♈ Aries | 75 | 50 | 80 | 55 | 90 | 45 | 65 | 45 | 90 | 55 | 80 | 50 |
| ♉ Taurus | 50 | 75 | 50 | 80 | 55 | 90 | 45 | 65 | 45 | 90 | 55 | 80 |
| ♊ Gemini | 80 | 50 | 75 | 50 | 80 | 55 | 90 | 45 | 65 | 45 | 90 | 55 |
| ♋ Cancer | 55 | 80 | 50 | 75 | 50 | 80 | 55 | 90 | 45 | 65 | 45 | 90 |
| ♌ Leo | 90 | 55 | 80 | 50 | 75 | 50 | 80 | 55 | 90 | 45 | 65 | 45 |
| ♍ Virgo | 45 | 90 | 55 | 80 | 50 | 75 | 50 | 80 | 55 | 90 | 45 | 65 |
| ♎ Libra | 65 | 45 | 90 | 55 | 80 | 50 | 75 | 50 | 80 | 55 | 90 | 45 |
| ♏ Scorpio | 45 | 65 | 45 | 90 | 55 | 80 | 50 | 75 | 50 | 80 | 55 | 90 |
| ♐ Sagittarius | 90 | 45 | 65 | 45 | 90 | 55 | 80 | 50 | 75 | 50 | 80 | 55 |
| ♑ Capricorn | 55 | 90 | 45 | 65 | 45 | 90 | 55 | 80 | 50 | 75 | 50 | 80 |
| ♒ Aquarius | 80 | 55 | 90 | 45 | 65 | 45 | 90 | 55 | 80 | 50 | 75 | 50 |
| ♓ Pisces | 50 | 80 | 55 | 90 | 45 | 65 | 45 | 90 | 55 | 80 | 50 | 75 |
Element combinations at a glance
- Fire and Fire, Earth and Earth, Air and Air, Water and Water: shared language and instincts, with shared blind spots.
- Fire and Air: ideas and action feed each other.
- Earth and Water: practical care and emotional depth support each other.
- Fire and Earth, Fire and Water, Earth and Air, Air and Water: different starting points, so these pairs trade ease for variety and need clearer communication.
Who may find this useful
People use sign comparisons for several reasons: to start a conversation with a partner or friend, to explore how a family member or colleague may see things, to learn the vocabulary of astrology, or simply for entertainment. It works best as a light, shared activity. It works poorly as a way to decide whether to start, continue or end a relationship.
Common mistakes and limitations
- Treating the Sun sign as the whole person: Moon, Venus, Mars and the Ascendant shape how a person relates. The Synastry Calculator looks at those.
- Ignoring sign-change dates: if your birthday is near the 20th to 23rd of a month, check your sign with the birth time.
- Reading the number as a prediction: it describes a convention, not an outcome.
- Mixing zodiac systems: the Sun signs here are tropical (Western). A Vedic Sun sign can be the previous sign.
- Using it to judge another person: understand people through what they actually say and do.
Frequently asked questions
How does a zodiac compatibility calculator work?
It compares the positions of two signs on the zodiac wheel. The distance between them (0 to 6 signs) gives the traditional sign relationship, such as a trine or an opposition, and the elements and modalities describe how the two temperaments tend to meet. The tool turns that framework into a plain-language reading and a symbolic rating.
Which zodiac signs are the most compatible?
In the traditional framework, signs in a trine (same element, such as Aries, Leo and Sagittarius) and in a sextile (for example Aries and Gemini) are rated as the smoothest. That is a statement about ease, not about happiness: smooth pairings can drift, and “harder” pairings often work well when both people communicate. No pairing is ruled out.
Can I check zodiac sign compatibility by date of birth?
Yes. Enter a date under either person and the tool finds the tropical Sun sign. If the date is one on which the Sun changes sign, the tool tells you both possible signs, because the answer then depends on birth time and place, and asks you to choose.
Does a high compatibility rating mean we will be happy together?
No. The rating is a symbolic convention based on one layer of astrology, the Sun signs. Communication, values, timing, boundaries and effort matter far more than any sign pairing. Treat the number as a talking point.
What if we share the same Sun sign?
The framework calls this a conjunction. It tends to bring quick familiarity and shared humour, and also doubles shared habits and blind spots. The tool rates it 75 and explains both sides.
How is this different from Vedic kundli matching?
Vedic matching (Ashtakoota or Guna Milan) usually compares the Moon signs and nakshatras of two people using a point system out of 36. This calculator compares Western Sun signs and does not use that system. If you want a chart-based comparison, try the Synastry Calculator.
Does this use my Moon sign or Rising sign?
No, it uses Sun signs only. You can find your other signs with the Moon Sign Calculator and Rising Sign Calculator, and compare complete charts in the Synastry Calculator.
Is my information saved?
The comparison runs in your browser and the signs or dates you enter are not sent to the server by this tool. Ordinary hosting logs and other website technologies may work separately; see the Privacy Policy.
Related tools and resources
Keep exploring, or read how SOULTRIANGLE documents its methods.
Our commitment to transparency
We explain the method, show the working and aim to correct problems when they are reported. If you spot an error, please use our Contact page and include the tool name and a non-sensitive example.
Last updated: October 18, 2026 · Method: sign distance, elements, modalities and polarity from traditional Western astrology; symbolic rating convention.