Bazi Compatibility Calculator

What bazi compatibility actually measures

Bazi compatibility — also written ba zi compatibility or Four Pillars compatibility — compares two birth charts to gauge how two people fit. In bazi, your moment of birth converts into four pillars: year, month, day, and hour, each a pairing of one Heavenly Stem and one Earthly Branch. Those eight characters (八字, literally "eight characters") describe your elemental makeup and temperament. A compatibility reading sets two such charts side by side and asks a practical question: where do these two energies support each other, and where do they strain?

What separates a genuine bazi love compatibility reading from a generic zodiac-sign quiz is determinism. Chinese astrology compatibility here isn't a personality vibe or a Western-astrology skin translated into Chinese imagery — it's a fixed computation. The same birth date and time always produce the same chart, and the same two charts always produce the same score. There is no guessing and no daily-horoscope drift: the four pillars are calculated from the calendar, and the interactions between them follow rules that are centuries old.

This calculator is free, needs no signup, and runs instantly in your browser. It reads the things classical practice cares about — how the two Day Masters interact, whether your Five Elements complement each other, and how your year and day branches relate — then blends them into love, communication, and long-term stability scores plus an overall figure. Nothing is stored or linked to you. Treat the result as a thoughtful reference for understanding a relationship, not a fortune or a verdict on your future.

He hun: how Chinese marriage matching worked

For most of Chinese history, marriage matching was called 合婚 (hé hūn), literally "combining the marriage." Before a wedding was agreed, a matchmaker would exchange each family's 八字 — the bride's and groom's eight characters written on red paper — and a fortune-teller would compare them. The pairing was checked for clashing zodiac branches, for whether the elements balanced, and for whether the union looked stable and prosperous. A poor match could call off an engagement; a good one reassured both families they were building something durable.

Modern practice keeps the analytical core and drops the fatalism. Few couples today let a chart decide whether they marry, but bazi marriage compatibility survives as a lens for understanding each other — a structured way to see where two temperaments naturally align and where they'll need patience. The reading names tendencies, not destinies: a challenging score describes work to do, not a relationship doomed to fail.

This tool follows the traditional method faithfully while staying transparent about what it does. It compares the same components a classical he hun reading examined — Day Master interaction, Five-Element balance, and branch harmony or clash — using deterministic calculation rather than intuition, so nothing depends on a single practitioner's mood or memory. You can see every component that feeds your score, which is the honest version of a practice that was once a closed art passed between masters. It is a reference for reflection and self-understanding, never a substitute for how two people actually choose to treat each other day to day.

Day Master interaction: the five dynamics

The Day Master is the Heavenly Stem of your day pillar — the single character that represents you in the chart. In compatibility, the interaction between two Day Masters sets the baseline chemistry, and it falls into one of five types. The strongest is the Five Combinations (天干五合): five specific stem pairs — Jia-Ji, Yi-Geng, Bing-Xin, Ding-Ren, and Wu-Gui — that the tradition treats as a natural, magnetic bond. Next is the generating cycle, where one stem's element feeds the other (Wood feeds Fire, Fire feeds Earth), a nourishing, supportive dynamic.

The remaining three: sharing the same element reads as kinship and easy familiarity; a control relationship across opposite yin-yang polarity is the classical 正官 / 正財 pairing, a balanced, respectful tension that traditionally underpins committed marriage; and a control relationship with the same polarity — the 七殺 / 偏財 dynamic — runs hotter and needs conscious work. The word "control" sounds ominous, but in classical thought a controlling relationship is what gives a partnership structure and drive; it only becomes strained when the polarities match and nothing tempers the push. Because this component captures how well you understand each other, it weighs most heavily in your communication score. None of the five is a dead end; each simply describes a different rhythm to learn, and couples in every category build happy, lasting relationships.

Five-Element complementarity: supplying what's missing

Every bazi chart carries a distribution across the five elements — Wood, Fire, Earth, Metal, and Water. A perfectly even chart would hold a 20% share in each; in reality, everyone leans strong in some and short in others. Compatibility compares the two distributions and asks whether each person supplies the elements the other lacks. When your partner is strong exactly where your chart runs thin — and vice versa — you cover each other's deficits, and the reading scores that coverage highly.

This "supply what the other lacks" idea is the classical lens for a supportive union, and it is why complementarity carries the most weight in the long-term stability score. The reading treats an even 20% share in each element as balance, then measures how far below that line each person falls and whether the partner's surplus can cover it. Two people who share the same gaps may feel similar and get along easily, but neither naturally balances the other, so their blind spots can compound over the years. Two who complement each other tend to grow steadier together than either is alone. The calculator marks which elements each partner covers for the other, so you can see exactly where the balance — or the overlap — lies, rather than taking the score on trust.

Branch relations and the spouse palace

Earthly Branches — the twelve signs behind the Chinese zodiac — interact through a fixed set of relationships. The harmonious ones are the Six Harmonies (六合), the best pairing, and the Three Harmony trine (三合). The challenging ones are the Clash (沖, the most difficult), Punishment (刑), Harm (害), and Break (破); two identical branches read as a mirror, and anything else is neutral. This calculator reads these relations on two branches: the year branches (your zodiac pair) and, weighted more heavily, the day branches.

The day branch matters more because it is the spouse palace (夫妻宮) — the position classical bazi ties most directly to marriage and intimate partnership — so its relationship leans into your love score above all, while the year-branch zodiac pair plays a lighter, supporting role. Some branch pairs carry mixed traditional signals, reading as both harmonious and clashing depending on the school; when that happens we classify by the dominant relation, giving precedence to harmony first so a genuinely warm pairing isn't buried under a secondary clash. And a clash is never a stop sign: plenty of lasting couples share a clashing branch and simply learn to give each other room, which is exactly why we read it as one signal among several rather than the whole story.