Big Three compatibility
calculator — Sun, Moon and Rising, compared
Your Big Three are the foundation of any birth chart: the Sun (who you are at the core), the Moon (how you feel) and the Rising sign (how you come across). This calculator compares all three levels between you — free, with a harmony score and a clear read per level.
Sun, Moon and rising for both of you side by side — the fastest read on your connection.
Person 1 — you
When were you born?
The date sets the Sun, Moon and every planet.
Three steps to your Big Three comparison
Enter both birth data sets
A date for each of you is required. Time and birthplace unlock the Rising level — without them we compare Sun and Moon, which is already half the story.
Calculate the Big Three
We build both charts from your data with the Swiss Ephemeris engine and read out Sun, Moon and Rising for each of you.
Read it level by level
Each level gets the sign pair, a harmony score and a plain-language read — what pulls, what chafes, where you can grow.
Sun, Moon, Rising: three levels of a connection
The Big Three are the three points that shape a chart most: the Sun (who you are at the core), the Moon (what you feel when nobody is watching) and the Rising sign (how you come across). The calculator compares each level on its own and then weights them. The Sun counts 40 percent, the Moon 35, the Rising 25. Without birth times it uses Sun and Moon only — 55 to 45.
| Level | Stands for | Changes sign | Weight in the calculator |
|---|---|---|---|
| Sun | Core, basic direction | about every 30 days | 40% |
| Moon | Feelings, need for closeness | about every 2.5 days | 35% |
| Rising | Impression, first contact | about every 2 hours | 25% |
That is why the Rising sign needs the time: it moves through a whole sign in about two hours. The Moon is tricky on days when it changes sign. If you calculate without a time on such a day, double-check the Moon sign in the Moon sign calculator.
What a difference per level means
- Matching Suns, different Moons: you want the same from life but comfort each other differently — one needs to talk, the other needs an hour alone.
- Matching Moons, different Suns: home feels easy, yet big decisions pull you in different directions.
- Matching Rising signs: the first impression clicks at once; whether it lasts is shown by Sun and Moon.
Check it against a real scene: how did you find your way back to each other after your last argument? That is the Moon level. Your own Big Three profile without a partner is in the Sun, Moon and Rising calculator, and how each sign ticks on its own is in the zodiac sign portraits.
Big Three — frequently asked questions
- What are the Big Three in astrology?
- Sun, Moon and Rising sign — the three most important points of a birth chart. The Sun describes your core self, the Moon your emotional life, the Rising sign how you come across. Together they say far more about a person than the zodiac sign alone.
- Why isn’t the zodiac sign enough for compatibility?
- Because your zodiac sign is only the Sun. Two people can have "incompatible" sun signs and still harmonise beautifully — because their Moons understand each other, or their Rising signs strike the same everyday tone. The Big Three comparison shows all three levels.
- What if we don’t know a birth time?
- Then we compare Sun and Moon — the two inner levels. The Rising sign depends on the exact time and birthplace, because it changes roughly every two hours. Add the times later and the comparison completes itself.
- How is the harmony score calculated?
- Deterministically, from classic astrology logic: signs of the same element harmonise strongly, fire with air and earth with water complement each other, square configurations create friction. Modality and the geometric relationship of your signs are added on top. Same input, same result — no random generator.
- Is a low score a bad sign?
- No. A low score means your energies differ and need translation. Those couples often grow more than couples with pure harmony. The score shows how much work the connection carries — not whether it is worth it.
Three levels, three honest answers
Sun — who you are at the core
Do your basic natures fit? The Sun level shows whether your life directions amplify each other or work against each other — and what you can make of it.
Moon — how you feel
The Moon level is the least visible and often the most important: how do you each handle feelings, and what does each of you need to feel safe? This is where relationships hold or fray.
Rising — how you land on each other
First impressions, the everyday tone, the chemistry in the room: the Rising level shows how you come across to each other day to day — it needs both birth times.
One score per level, clearly derived
Each level gets a 0–100 harmony score — derived from element, modality and how your signs sit relative to each other. No randomness, no black box.
More calculators & tools
Compatibility chart
The full comparison: every planet, every link.
Venus & Mars calculator
How you love and what drives you — date of birth only.
Zodiac sign compatibility
Pick two signs, see the result instantly — no birth data.
Your Big Three
Start with your own: Sun, Moon & Rising at a glance.
Birth chart
Your full chart — every planet, house and aspect.
Learn astrology
Read what happens between two charts yourself, in 30 days.
Reviewed by Stina Garbis · Tarot & Astrology ReaderReady to compare your Big Three?
Sun, Moon, Rising — three levels, three harmony scores, one honest read. Free, no sign-up.
Compare Big Three nowFree, no sign-up.