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Free Bazi Calculator
Your Bazi chart, made clear. Enter a Gregorian birth date and a local birth time. We will not ask for your name, email, or account.
For learning and reflection. Bazi is a traditional cultural framework. This calculator documents the method it uses and its current boundaries. Do not use a chart as medical, legal, financial, or other professional advice.
What you will see on the chart
What this free Bazi calculator shows
Every output below comes from the same in-browser engine. No signup, no email, no account. Birth city is collected only for clarity and is not used in the calculation.
- Four Pillars (八字) — Year, Month, Day, Hour — A snapshot of the four moments of birth. Each pillar is one heavenly stem paired with one earthly branch. When the birth time is unknown, only three pillars are shown.
- Day Master (日主) — The stem on the day pillar — the most common starting point in English-language Bazi. We print its element and yin/yang polarity as a reference observation, not a personality verdict.
- Five Elements (五行) — Wood, Fire, Earth, Metal, Water — A descriptive tally across the visible stems and branches. The total is 8 when the hour is known and 6 when it is not. We do not score you or recommend remedies.
- Ten Gods (十神) — A fixed label printed next to every visible stem, showing how each stem relates to the day master through the five-element cycle and yin/yang. Structural, not predictive.
- Hidden Stems (藏干) — A fixed, documented map of the stems inside each earthly branch (main, secondary, residual). The engine never invents hidden stems — they come from a published table.
- Unknown birth time mode — Tick "I do not know the birth time" and the hour pillar is hidden. The day master, five elements, Ten Gods and hidden stems are still computed from the three remaining pillars — read them as illustrative.
- Optional AI explanation (Beta) — After the chart renders, a click-triggered button can send the already-calculated chart to an external language model for a plain-language walk-through. Your birth date, time, and city are never sent.
Evidence — what we publish and what we do not claim
How we know the calculation matches the reference. The four pillars come from the reference library lunar-typescript 1.8.6 (MIT, sect 2). The published boundary matrix has 30 published cases and our engine agrees with the reference on 30 of 30. This is a regression check against the same library rule, not an independent academic or expert validation. Birth city, longitude, historical time zones, true solar time and DST are not applied. Read the full methodology.
How it works
- You enter a date, time, and (optionally) city. No name, no email, no account. Birth data is held in volatile page memory only — a refresh or closing the tab clears it. It is never written to disk or to a server.
- We calculate four pillars. Year, month, day, and (if time is known) hour. Each pillar is made of two Chinese characters: a heavenly stem on top and an earthly branch on the bottom.
- We read the day master. The day’s stem is called the day master. It is the most common starting point in Bazi, not a personality verdict.
- We count the five elements. Wood, fire, earth, metal, water. The counts are descriptive, not prescriptive. We do not score you or recommend remedies.
Learn Bazi
Start with the basics before you calculate
Three short, plain-English guides explain the framework BaziTrace uses — what it counts, what it deliberately leaves out, and how to read a chart without over-reading it.
- What is Bazi? — A neutral overview of the four pillars (八字) and what BaziTrace calculates from them.
- What is the day master? — Why the day stem is a starting observation, not a personality verdict.
- Reading the five elements — How the wood / fire / earth / metal / water tally is counted, and what it does not say.
Frequently asked questions
No. The calculator is free, and we do not collect a name, email, gender, or account. The site has no login, no sign-up, and no saved history.
The four pillars come from the reference library lunar-typescript 1.8.6 (MIT), which handles the solar-term ephemeris and the day-boundary convention internally. The methodology page explains the civil-time convention and the boundaries the engine does not yet resolve.
We do not claim that. The four-pillar math is a well-known calculation, but the rules around solar terms, day boundaries (midnight vs. true solar), and the city/timezone correction all change the answer. We document every choice on the methodology page so you can decide for yourself.
No. Birth data is held only in volatile page memory in this browser session; a refresh or closing the tab clears it. It is not written to localStorage, sessionStorage, cookies, the URL, or any server.
No. Bazi is a traditional framework, not a clinical, legal, or financial tool. Even when the engine is fully validated, it would still be one of many lenses to think with, not a basis for serious decisions.